Tank Lighting cycle

Dear Amanda:

Congratulations on your new Sunbursts! I’ll do my best to address your questions and concerns below.

The exact photoperiod or on-off time for your aquarium lights is not critical for seahorses at all, but I do recommend providing them with a simulated dusk and dawn before the main aquarium lights go on our off, as discussed below:

Lighting the Seahorse Tank

When it comes to lighting, seahorses do not have any special requirements other than the fact that most species prefer low to moderate light levels rather than excessively bright light. They have a corrugated retina especially rich in rods, which gives them excellent visual acuity under twilight conditions and low light levels in general. But this does not mean that they shun bright light, just that they appreciate shady retreats as well as brightly illuminated areas.

In actual practice, seahorses will do well under any type of lighting you prefer providing well-shaded areas are available to them and overheating does not become a problem. Most hobbyists find that a standard fluorescent light fixture works very well for seahorses. An ordinary daylight fluorescent bulb will provide plenty of illumination for a seahorse tank and produce enough light for macroalgae and marine plants.

However, high-intensity lighting can have an adverse effect on the coloration of seahorses and it’s best to avoid displaying colorful seahorses under metal halide lighting. In addition to providing high-intensity lighting, the metal halides also tend to generate a lot of heat, and as you are aware, heat stress can be very detrimental to seahorses. In addition, seahorses don’t like excessively bright light and they may go into hiding, seeking shaded areas amidst the rockwork, if the lighting is too intense for their comfort level. And the seahorses won’t look their best and brightest under metal halides because they will produce excess melanin (black pigment) in order to protect themselves against the harmful ultraviolet radiation they associate with intense light, and darken as a result. For instance, Jorge Gomezjurado reports "…I have exposed yellow seahorses to strong metal halide and they have turned black in few hours." Some hobbyists who keep a selection of handpicked live corals with their seahorses like to use metal halides or other high-intensity lighting systems for the sake of the corals, but it would be a shame to display brightly colored seahorses under such strong lighting and cause them to darken.

Personally, I like to provide my seahorses with a natural day/night period that includes twilight periods at "sunrise" and "sunset." To accomplish this, I like the power compact (PC) light fixtures that include two tubes — one actinic and one daylight fluorescent — with dual ballasts so that each ballast can be placed on a separate automatic timer. I like to have the bluish actinic come on before the daylight tubes and stay on after the daylights go off, thereby providing a simulated dusk and dawn (Giwojna, unpublished text). This is important for seahorses since they conduct most of their courting and breeding in the early morning hours under twilight conditions. It’s a neat effect and fish and invertebrates can then anticipate "lights out" rather than being plunged into total darkness at night or suddenly thrust into bright light in the morning. I also adjust the timers to lengthen or shorten the daylight periods in accordance with the changing seasons. I find that maintaining a natural cycle this way aids reproduction (Giwojna, unpublished text).

In short, I find PC lighting to be a good compromise for a seahorse system. Power compacts provide plenty of light for macroalgae or the seahorse-safe soft corals in a modified reef system without being too bright or generating too much heat, and the dual ballast system allows for a natural day/night rhythm that changes with the seasons. The resulting dusk and dawn facilitate courtship and help the seahorses maintain a natural reproductive cycle (Giwojna, unpublished text).

You can accomplish the same thing and provide the twilight conditions for your seahorses simply by turning on the room lights a half hour or an hour before you switch on the aquarium reflector at the start of the day, and then leaving the room lights on for a while after you switch off the aquarium light at night.

In short, Amanda, simulated twilight periods are great for providing the seahorses with an added sense of security and helping to stimulate courtship and breeding, but other than that, the photoperiod you maintain it’s really not that important. Other than providing a simulated dusk and dawn, if possible, there is no real optimum photoperiod that applies to seahorses in general, other than the fact that it’s important to provide a total of 12 hours of light or more daily if you want the seahorses to breed. (A photoperiod that provides significantly less than 12 hours of light can affect the secretion of hormones and effectively prevent breeding in some seahorses.)

If you want to encourage breeding, or your seahorses have been slow to breed, try extending the twilight periods at the start and end of each day (that’s primarily when courtship and daily greetings are conducted) and increase the hours of daylight you provide to well in excess of 12 hours. You can also try varying the hours of daylight in accordance with the changing of seasons to provide environmental clues or a seasonal cycle to help stimulate the secretion of gonadotropin and other key hormones, but that is much more important for wild-caught seahorses then domesticated seahorses.

For all intents and purposes, you really can’t go wrong no matter what lighting system you chose as long as you provide both shaded areas where your seahorses can escape from the light altogether and well-lit areas where they can bathe in bright light as they please. You will find your seahorses will move into and out of the light often, seeking the comfort level that suits them at the moment.

When it comes to coloration, the lighting you choose can have a profound effect on the colors that your seahorses assume for better or worse under certain circumstances. For instance, as noted above, excessively bright lighting can sometimes cause colorful seahorses to darken and turn brown or black as a protective mechanism.

Rather then metal daylights or halogens, or other high-intensity lighting systems, the right combination of fluorescent lights will bring out the best colors in your seahorses, in most instances. Paul Groves, curator at Underwater World in Perth, recommends combining a triphosphor (6500k) fluorescent tube with a Phillips TL Blue fluorescent tube to produce the best overall lighting for a seahorse exhibit. After much experimentation, he found the above combination of lights really encouraged the coloration of the seahorses as well as being aesthetically pleasing to the eye. He reports that the diversity in colors displayed by Hippocampus subelongatus was much less under any other lighting. This combination of fluorescent lights would provide plenty of illumination for macroalgae and should work great for most seahorse setups that do not include live corals.

But, in your case, Amanda, since you already own orange Brazilian seahorses (Hippocamus reidi), I strongly urge you to consider displaying your seahorses under Gro-lux fluorescent lighting. Osram Gro-lux bulbs put out wavelengths of light that are concentrated toward the red end of the spectrum. They are intended to stimulate better plant growth, but have the added affect of greatly enhancing any red or orange or purple colors they illuminate. When bathed in Gro-lux light, bright red or orange seahorses literally glow!

In fact, when I first discovered this effect — with a Red Philippine Lobster (Enoplometapus sp.) in a specialty tank — I believed I was witnessing actual fluorescence. The seven-inch bulldozer of a crustacean was covered with sensory bristles that made it look almost fuzzy, and under the Gro-lux bulb, the extraordinary excavator was instantly suffused with a fiery radiance that dazzled the eye. At first I thought it’s exoskeleton was glowing, and I hypothesized that perhaps the chitin was infused with the type of calcite crystals that fluoresce under ultraviolet, and which perhaps could be similarly excited by the wavelengths emitted by the Gro-lux bulb.

I only realized the truth when I added the same type of bulb to an aquarium containing, among other choice specimens, a gorgeous purple-and-yellow Royal Gramma and a rare red-orange Hippocampus erectus. Now, that seahorse was very colorful under any kind of lighting, but as soon as that Gro-lux lamp switched on, the erectus was ablaze with a shade of brilliant Day-Glo orange ordinarily only seen from neon signs, nuclear meltdowns, and psychedelic posters displayed under UV (for those of you old enough to recall them). The stunning steed shone with a luminous aura, awash with glorious orange glow that made it look like it was swathed with liquid fire. Suddenly, it was the color of red-hot lava, aflame with a blinding orange incandescent, and the result was truly spectacular. Then my shy Royal Gramma emerged from it’s sleeping cave to keep the seahorse company, and it’s magenta end was immediately suffused with a dazzling hot-pinkish purple glow that ended abruptly where it’s yellow half began. That made it obvious that the new bulb was accenting colors at the red and violet regions of the spectrum, which are precisely the wavelengths of light chlorophyll absorbs best.

The reflected Gro-lux light was responsible for the breathtakingly beautiful effect, and it will produce the same scintillating display in your aquariums. It would certainly set red and orange Brazileros (Hippocampus reidi) aglow, as well as Mustangs or Sunbursts (H. erectus) in their red to orange color phases. Pink to purple seahorses should be similarly enhanced under Gro-lux lighting. Fire Reds that approach true scarlet or crimson would no doubt blaze brilliantly, but I’m less certain what effect it would have on specimens that tend more toward auburn or which display that rich mahogany luster instead. And it would have no effect whatsoever on black or brown or yellow or green seahorses, which would absorb the light rather than reflecting it. Suffice it to say if you own red, orange, or purple seahorses, you should also own Gro-lux bulbs in order to display them in all their glory!

Your best bet for locating Osram Grolux florescent tubes is to look at garden centers and nurseries, since they are primarily intended for stimulating plant growth rather than for aquarium use.

Sunbursts are predisposed to display the "sunset" colors when conditions are to their liking, Amanda, which means that they are normally a vivid yellow to orange in coloration when they are looking their best and brightest But they may darken in response to stress and a number of other factors such as the aquarium lighting can also affect their coloration.

If your Sunbursts are showing a brownish color phase at the moment, most likely the new arrivals just need a little more time to adjust to their strange, new surroundings and start to feel at home. The ideal conditions they are accustomed to at the Ocean Rider aquaculture facility (an open system with natural seawater, natural sunlight, and vast amounts of swimming space) are much different than the conditions in the average home hobby tank, which is a closed system with artificial saltwater, artificial lighting, and limited swimming room. I suspect they will brighten up and reveal their true colors again once they have had more time to make the adjustment to their new environment.

But there are some things you can do to encourage your seahorses to retain their bright coloration aside from adjusting the lighting, Amanda. For instance, This is normally what I advise hobbyists when they ask about changes in coloration or how to keep their seahorses looking their best and brightest:

Coloration in Seahorses

When it comes to their color pattern, seahorses are not like most other marine fish — rather, they are truly the chameleons of the sea with a propensity for changing color in response to a wide range of environmental factors, hormonal influences, and behavioral interactions.

It’s important to understand that although Ocean Rider (OR) seahorses have been endowed with a palette of pigments rich in bright hues, they are not like albinos or lutino or melanistic mutants that are "locked" into their white or yellow or black coloration respectively. Such mutants are a certain color because they are genetically unable to manufacture other pigments; ORs are not. Rather, ORs are genetically equipped to express a wide range of vivid colors, and each type has a built-in predisposition towards a wardrobe of certain shades. But they can and will change colors to reflect their mood, environment, and well-being, as well as to interact with other seahorses.

Seahorses accomplish color changes through the contraction or expansion of pigment cells known as chromatophores. Each chromatophore is a contractile cell or vesicle containing liquid pigment and capable of changing its form or size, thus causing changes of color in the skin of the animals that possess them. The chromatophores may be under nervous control and able to change very rapidly or under hormonal control and able to change only relatively slowly.

In seahorses, the chromatophores are branched (dendritic) cells, within which the color pigment can be moved. When a chromatophore contracts, all of its pigment is concentrated in one small spot in the center of the cell, resulting in the loss of color in the fish. When a chromatophore expands, the pigment spreads throughout the entire cell to all its branches, resulting in bright color.

Different types of chromatophores contain different pigments such as melanin (black), xanthin (yellow), lipochrome (orange), erythrin (red) and so on. The different types of chromatophores are named according to the type of pigment they contain (e.g., melanophores, erythrophores and xanthophores). These specialized pigment cells are usually stacked upon each other or clustered in groups. Hippocampus is typically endowed with 3 or 4 different types of chromatophores, and all other colors are derived from these 3 or 4 basic pigments. The exact color the seahorse displays at any given time therefore depends on the concentration of these pigment cells, how close the cells are to the surface of the skin, and which chromatophores are expanded or contracted at the moment.

For example, seahorses have no blue pigment cells, but the color blue can be approximated nonetheless. A low concentration of melanin (black pigment) deep in the dermal layer gives the skin of the fish a bluish cast. Achieving a blue tint in this way while simultaneously expanding xanthophores (yellow pigment cells) produces shades of green, and maintaining a bluish background color while opening erythrophores (red pigment cells) yields shades of purple and violet. Likewise, a seahorse that has no orange pigment cells can still assume a bright orange coloration by simultaneously expanding its xanthophores (yellow pigment cells) and erythrophores (red pigment cells) to the fullest. The exact shade of orange it becomes and its brightness is determined by the proportion of yellow to red cells it opens, how fully they are expanded, and how close to the skin’s surface they are. Obviously, a seahorse that is black has all its melanophores expanded and a seahorse that is white has ALL of its chromatophores contracted so that all the wavelengths of visible light are reflected back to the observer, and so on.

In seahorses, melanophores are the most common of these pigment cell types. They contain the pigment melanin, which gives most seahorses their typical black or dark brown coloration. Essentially melanin absorbs the entire visible light spectrum and looks black because no light is reflected back to the observer. When a melanophore is open and fully expanded, the melanin it contains is dispersed throughout the cell, and when all the melanophores are opened at once, melanin is distributed evenly across the surface of skin, rendering the seahorse black. Seahorses typically respond to stress by expanding their melanophores and darkening this way.

The different types of pigment cells seahorses possess varies from species to species. Hence, not all seahorses have the same palette of colors at their disposal. Some seahorses can never turn red because they lack erythrophores; red is simply not in their wardrobe. In general, tropical seahorses tend to have brighter colors in their repertoire than temperate species. And deep-water seahorses often have more red and orange pigment cells than other seahorses. In order words, different seahorse species have different coloration due to the differential proliferation of chromatophore cell types.

Colorful Ocean Riders, for example, are not homozygous recessives nor or they mutations that are unable to manufacture certain pigments altogether. But they do exhibit differential proliferation of chromatophores and this gives each type a predisposition to display certain colors. Mustangs have a preponderance of melanophores, for instance, and tend to be dark (earth tones) or cryptically colored most of the time. But ‘stangs also have bright pigment cells and they can brighten up when the occasion calls for it, such as during courtship or when competing for mates.

I own a pair of these spirited steeds myself, and have watched them go through a number of color phases from month to month. One has settled on gray-green as its base coloration for the moment, and the other ranges between rust, burnt umber, and orange, but always with contrasting beige bands. Last season, the male adopted a rich ochre yellow as his everyday attire (still with the same beige bands, though), while the female displayed a dark purplish ensemble with definite greenish highlights. When courting, they consistently brighten to a pearly white and a creamy yellow respectively. They make a handsome couple, and I find my Mustangs to be very attractive specimens in all their guises.

As for their coloration, Sunbursts are equipped with a full range of chromatophores (pigment cells) and can display a wide range of colors, but they are predisposed towards the sunset colors (yellow, gold, peach and orange) when conditions are to their liking. They have proportionally fewer melanophores (black pigment cells) than Mustangs, which are typically dark brown or black, so the background or base coloration of the Sunbursts tends to be lighter. Yellow and orange specimens predominate, but they also display whitish, tan, pearly and even brown color phases at times. You can expect your Sunbursts to go through a number of color phases and color changes over the months.

Sunbursts have fully functional melanophores, albeit somewhat fewer of them, in addition to their bright pigment cells and they will darken in response to stress or change their coloration to reflect changing circumstances and conditions. It sounds like your water quality is right where you want it, Amanda, but there are any number of environmental conditions that can also affect the coloration of seahorses, often by affecting the ability of chromatophores to contract and expand. These include the following factors:

Stress — seahorses often respond to stress by darkening.

Emotional state — when excited, seahorses typically brighten in coloration, reflecting a state of high arousal. On the other hand, fear, anxiety and distress are generally accompanied by dark, somber hues.

Social interactions — seahorses often brighten during their courtship displays; pair-bonded seahorses likewise brighten during their morning greeting rituals, and rivals go through characteristic color changes (see below) during their confrontations and competitions.

Competition for mates — dominant individuals brighten; subordinate seahorses darken in submission.

Hormonal influences — juvenile seahorses may change coloration when they hit sexual maturity in response to a change in their hormonal levels.

Poor water quality — high levels of nitrogenous wastes (e.g., ammonia, nitrite or nitrate) can cause chromatophores to contract and colors to fade.

O2/CO2 — low oxygen levels (or high CO2 levels) can cause colorful seahorses to fade and they will blanch when subjected to hypoxic conditions.

Background colors — seahorses will often change color in order to blend in with their immediate surroundings.

Medications — some antibiotics and malachite-green-based remedies negatively affect color.

Tankmates — seahorses may change their base coloration to blend in with the rest of the herd or to match their mate (or a potential partner). This can work both ways: a dark seahorse may brighten up and assume vivid hues when introduced to an aquarium with bright yellow or orange tankmates, just as a brightly colored seahorse may darken and adopt subdued coloration when placed amidst drab tankmates. Of course, seahorses are not responding to peer pressure when they conform in this manner; rather, this is probably instinctive behavior. In nature, it’s not healthy to be too conspicuous and stick out in a crowd since an individual that stands out from the rest of the herd draws the attention of potential predators to itself.

Temperature — chromatophores tend to contract at high temperatures (above the seahorse’s comfort zone), causing colors to fade; cooler temps within their optimal range can make pigment cells expand, keeping colors bright.

Disease — skin infections (bacterial, fungal, or parasitic) can cause localized loss of pigmentation or discoloration of the affected areas.

Diet — seahorses cannot synthesize the pigments used in their chromatophores. It is therefore important to enrich their food with pigments such as carotenoids in a form that’s easy for them to absorb. If color additives are not provided, the chromatophores will gradually lose their pigments and the seahorse’s color can fade. Vibrance, for example, is exceptionally rich in Vitamins A and C as well as natural carotenoids, which are not found in Mysis relicta. This is important because the carotenoids are a class of yellow to red pigments, which include the carotenes and the xanthophylls. Like all cells, individual pigment cells have a limited life expectancy in the body and must be regularly renewed. Marine organisms cannot synthesize carotenoids, so if they do receive adequate amounts in their diet, they will have difficulty replenishing their red and yellow pigments. This means that the colors of bright yellow, orange, and red seahorses will gradually fade over time if their daily diet is lacking in carotenoids. So don’t neglect the enrichment step in your daily feeding regimen! If seahorses are fed a strict diet of Mysis relicta without additional enrichment, they may begin to develop dietary deficiencies over time, and both their health and coloration will eventually suffer.

Lighting — seahorses may darken in response to UV radiation or intense lighting (e.g., metal halides) as a protective measure, whereas bulbs that emit wavelengths of light shifted towards the red end of the visual spectrum (i.e., Grolux fluorescent tubes) can greatly enhance the coloration of red, orange or purplish seahorses to the point that they almost literally glow.

In short, you can expect your seahorses to exhibit a number of different color phases over the coming months and years. Expect them to display brighter colors when they get serious about breeding and courtship, for instance. And if they happen to adopt a colorful hitching post as their favorite perch or hang out, they may gradually change coloration to match their favorite resting spot.

All of the different factors mentioned above need to be addressed in order to keep your seahorses looking their best and brightest, Amanda. It sounds like your water quality is fine, and that you may want to adjust your lighting somewhat, but there are a number of other things that you can explore to influence their coloration and encourage them to display bright colors. These are discussed in some detail in a two-part article on coloration in seahorses that I recently wrote for Conscientious Aquarist online magazine. The first article explains how seahorses use their amazing color changing ability, while the second article explains how they accomplish their color changes and is loaded with tips for keeping colorful seahorses such as Sunbursts looking their best and brightest. You can read the articles at the following URL’s and enjoy Leslie Leddo’s magnificent photographs. Just copy the following URL’s and paste them into your web browser, and it will take you directly to the articles:

part one:
http://www.wetwebmedia.com/ca/volume_4/V4I1/hippocampus_color/Color_In_Hippocampus.htm

part two:
http://www.wetwebmedia.com/ca/volume_4/V4I2/hippocampus_color2/Color_In_Hippocampus2.htm

It’s an excellent idea to train your seahorses to be there frozen Mysis from a feeding station, Amanda, and it sounds like you have already made great strides along those lines. Here are some additional suggestions that you may find helpful when it comes to encouraging the rest of your seahorses to make full use of your feeding station.

First of all, there are a few factors to bear in mind when choosing the location for your feeding station.

For starters, it must be in a location that’s convenient for you to reach and observe, since you will be depositing the enriched Mysis in the feeding tray, watching closely to make sure that all your seahorses show up for chow and are feeding normally, with healthy appetites, and then removing any uneaten leftovers when the seahorses have eaten their fill.

Secondly, the feeding station should be located in an area with relatively low flow so that the seahorses can approach it easily, and more importantly, so that brisk currents don’t whisk the frozen Mysis out of the feeding tray or make it too difficult to guide the enriched Mysis into the feeding dish in the first place.

Finally, if the aquarium has a heavy population of bristleworms, micro-hermit crabs, or miniature brittle stars (micro stars), all of which have a liking — perhaps even an addiction — to that gourmet frozen Mysis we provide our seahorses, and they tend to converge on the feeding station at mealtime and steal the Mysis or just generally get in the way, many hobbyists find it useful to elevate their feeding tray in order to keep it out of the reach of such bottom scavengers.

Setting up your feeding station is simply a matter of selecting the type of feeding dish you prefer and setting it in place in the desired location, which should meet all the criteria discussed above. All that remains is to train your seahorses to come to the feeding station and eat, which normally is a very simple process that they often take care of on their own.

For example, most hobbyists use a feeding tube of some sort to deliver the enriched frozen Mysis to their feeding station. The feeding tube is simply a length of rigid, clear-plastic tubing, perhaps 1-2 inches in diameter, that’s long enough to reach all the way from the surface down to the feeding station. When the food is ready, they place the thawed enriched frozen Mysis in the top of the feeding tube, and it sinks slowly down the length of the tubing to be deposited in the feeding bowl or tray below. Often the seahorses will track the Mysis all the way down the tube to the end and be ready to snap it up as soon as it emerges over the feeding station, which is an added benefit of this method since it eliminates the need to train the seahorses to come to the feeding dish. The hungry horses will just naturally follow the sinking Mysis to its destination.

When you set up a feeding station, most seahorse pick up on it right away and respond to the new feeding method very well, as described above. However, sometimes there is a slow learner that needs to be trained to come to the new feeder. There are a couple of fairly simple ways to accomplish that, which usually work pretty well.

One way to get your seahorses up to speed on a new feeding station is to target feed them with a turkey baster, and once they are eating from the baster well, use it to lead them to the new feeding station. The old-fashioned ones with the glass barrels work best because the seahorses can see the Mysis inside the baster all the way as it moves down the barrel and out the tip. By exerting just the right amount of pressure on the bulb, great precision is possible when target feeding with a turkey baster. By squeezing and releasing the the bulb ever so slightly, a skillful target feeder can keep a piece of Mysis dancing at the very tip of the baster indefinitely, and hold the tempting morsel right in front of theseahorse’s mouth as long as necessary.

If you can do that, it is an easy matter to hold a morsel of Mysis at the end of the baster, and use this tantalizing tidbit to lure the seahorse toward the new feeders by holding it just out of reach and leading the hungry seahorse in the direction you want him to go before you allow him to take the bait. This may have to be done in several steps, and it may take a while for you to get the seahorses accustomed to taking food from the baster before you start making much progress, but eventually you’ll have the pupil perched close enough to the new feeder for you to drop the dangling Mysis inside the feeding station before you allow them to slurp it up. This method takes time and patience, but it allows you to make sure the seahorses are getting plenty to eat while they make the transition to the new feeders. And it’s a gradual conditioning process that will eventually work with even the slowest learners.

Net training is a similar technique to baster feeding that also works well and may be even easier to execute because it doesn’t require any skill with the baster or syringe. It involves first training the seahorses to eat the frozen Mysis from a small fish net (a fine-meshed brine shrimp net works best for this), which they learn to do rather readily. Once that is accomplished, the net serves as a portable feeding trough, which the seahorses will come to and follow anywhere in order to eat, so you simply use it to lead them to the new feeders. Your next step is to rest the net inside a feeding trailer feeding station while they eat from it. After a few days of feeding them like that, you simply dump the Mysis from the net into the new feeder, and they will happily dine from there from then on. The net or feeding tray contains the frozen food neatly and keeps it from getting strewn around the tank.

For example, here’s how Patti (one of our Club members) describes her net training process: "I use a small brine shrimp net — it is white. When I first got my seahorses I would target feed from this net — they lean in and take the shrimp. Once I got them to recognize that this net meant food, I started to sit the net down inside the bowl and let them eat from it there. After a few days I simply started to drop the shrimp from the net into the bowl. Now, they see the net and either jump on the net or go directly to the bowl. When they are hungry and I have not fed yet, they go to the bowl as if to say "Hey where is our breakfast?". It seems to work very well for us, it is also a good way to make sure they have food while I am at work. The tricky part was getting them to eat from the net at first but once they realized that it held the food they overcame any fear they had. It just takes about a week of patience…."

Believe me, training the seahorses to eat from your feeding station sounds a great deal more difficult than it actually is, Amanda. In most all cases, all you have to do is get one of the seahorses to snick up that first piece of shrimp from the feeding tray and your mission is accomplished. That first bold individual will happily continue to eat from the feeding station thereafter, and more importantly, very often the rest of the herd plays follow-the-leader and quickly learns from his example. Seahorses are real seagoing gluttons, ruled to a very large extent by their stomachs, and once the rest the seahorses see that first fast learner pigging out on gourmet shrimp, they usually can’t wait to get their share of the goodies too. (You have already accomplished this with the help of your female H. reidi, so I don’t think it will be long before the rest of the seahorses follow suit and begin using the feeding station as well.)

I would be remiss if I didn’t caution you that Hippocampus reidi are notoriously finicky eaters, however, Amanda. Some of our members have aptly described them as the "Morris the Cats" of seahorses. So if your seahorses are wild-caught reidi, you may need lots of patience and perseverance to train them to eat frozen foods and to keep them eating them readily. Captive-bred reidi should already be conditioned to eat frozen foods much more readily than wild caught Brazilians, though, and will be much easier to train to eat from the feeding station than their wild-caught counterparts.

Have you seen the Club’s usual feeding tips yet, Amanda? In case you haven’t, I’ll paste the suggestions for enriching frozen Mysis with Vibrance and target feeding seahorses and setting up a suitable feeding station for you below. (The carotenoids, xanthophylls, and natural color enhancers in the Vibrance will help your seahorses to produce and maintain their normal bright orange and yellow pigmentation.)

Whatever brand of frozen Mysis you obtain, for best results, it’s a good idea to fortify it with Vibrance before feeding it to your seahorses. In order to enrich it, the frozen Mysis is carefully thawed out and rinsed well to remove any excess shrimp juices, and then a VERY light dusting of the Vibrance is added to the Mysis while they are still just a bit moist. The Vibrance is then gently worked into the frozen Mysis and it usually adheres very well. The end result should be whole, completely intact Mysis shrimp that have acquired a reddish tinge to their head or anterior end. In actual practice, there are probably as many different ways of successfully thawing and enriching frozen Mysis as there are aquarists that use them; most everybody works out their own method of preparing the frozen Mysis that works best for their needs and busy schedule.

In case you haven’t seen them already, here are the Club’s usual feeding tips, Amanda:

Feeding Tips

(1) Tips for thawing and enriching frozen Mysis.
In order to prevent wastage and obtain the maximum benefit from this superb food, it must be thawed properly. This is especially important because once the Mysis are fully thawed, they are not refreezable (Adib, 2004). Most hobbyists tend to simply thaw their mysids in aquarium water, which has the virtue of thawing it quickly but is not the best approach. The faster the frozen shrimp is thawed, the more likely it is to be damaged in the process. We want the mysids to remain intact and lifelike; we don’t want the tissue of the Mysis to begin to breakdown in the process of freezing/thawing. The goal is to preserve the Mysis and retain all those precious shrimp juices when we thaw it, not to release their fluids into the aquarium water where it will only degrade the water quality and do your seahorses no good!
So don’t thaw frozen Mysis in 75°F-80°F aquarium water. Don’t nuke it in the microwave to defrost it! And don’t simply toss a chunk of frozen Mysis in your tank and let it float around until it thaws and releases individual mysids!
Nor should you thaw it in tap water, distilled water, or any other source of freshwater. You want to thaw the shrimp in water that is about as salty as their own bodily fluids so there is little or no difference in osmotic pressure. Freshwater will tend to move into the mysids as they thaw and can break down their integument and rupture cell walls as they swell; excessively salty water will tend to draw water out of the Mysis as they thaw, desiccating them in the process. Normal strength seawater is just right for thawing.
So the recommended method for thawing frozen Mysis is to use refrigerated saltwater from your aquarium. Keep a small jug of your artificial saltwater in your refrigerator and reserve this for thawing your mysids (Adib, 2004). Place a couple of ounces of the chilled saltwater in a small cup or similar receptacle and use that to thaw the shrimp. Break off a small chunk from the mass of frozen Mysis — just enough for one feeding or a day’s worth at most (with experience, you will soon learn exactly how much to use) — place it in the cup of saltwater and allow the Mysis to slowly thaw in the refrigerator for 30-45 minutes (Adib, 2004). Then take the cup out of the refrigerator and allow the thawed Mysis to warm up at room temperate for another 15 minutes (Adib, 2004). This method leaves the mysids perfectly intact and lifelike, and produces immaculate shrimp that need no further rinsing. (If you use another method for thawing the Mysis, it’s generally advisable to rinse the thawed shrimp in a brine shrimp net to prevent fouling of the aquarium water.) You are now ready to fortify the Mysis with the enrichment formula of your choice.
Carefully remove the individual thawed mysids from the thawing container using a plastic fork or a toothpick and gently deposit them in the bowl of a plastic spoon. The idea is to handle the shrimp as little as possible during the thawing and enriching process, since rough handling can cause the mysids to break apart. If your enrichment product is in powder form such as Vibrance (which I recommend), take a pinch of the formula, sprinkle it on the Mysis, and mix it in very gently (a plastic knife or similar instrument works well for this step). The orange power will adhere to the moist Mysis, and when you’re done, the head region (cephalothorax) of the mysids should be stained reddish. (If your preferred supplement is a liquid formula, just add a few drops to the Mysis and let it soak in.)
With a little practice, most hobbyists quickly work out their own technique for preparing enriched Mysis. The method outlined above works well for me and many other aquarists, but there are many other ways of defrosting and enriching the Mysis that work equally well. For instance, other hobbyists prefer to add a dusting of enrichment powder (or a few drops of a liquid supplement) to a chunk of frozen Mysis and gently mix it in (or allow it to soak in) as it thaws. One nifty way to do this is to break off my little chunk of frozen shrimp and place it on a square of wax paper, allow it a while to defrost, and then add a pinch of enrichment formula and roll the Mysis and power in the wax paper as though making a cigarette. This technique is trickier and takes a little experience before you can pull it off properly. The thawing and rolling/mixing process must be done very, very carefully or you may crush some of the Mysis and lose a lot of shrimp juice while preparing it. As always, if you’re doing it right, the heads of the individual Mysis shrimp should end up stained red, which is a feeding "trigger" captive-bred chowhounds find hard to resist. With a little practice, you will soon refine your own method for preparing frozen Mysis that works the best for your schedule and the needs of your herd.
But however you prepare it, it’s important to keep the enriched Mysis refrigerated until it’s used, and to use all the Mysis you thawed and enriched within 24 hours. For best results, the enriched Mysis should be used immediately after it’s prepared. Whether it’s been refrigerated or not, avoid using thawed and prepared Mysis that is 2 or 3 days old. We don’t want to offer our seahorses food that might have become laden with bacteria.

(2) When it comes to feeding, give new arrivals time to recover and settle into their new surroundings before you force the issue.
That’s a long haul from Hawaii, and it sometimes take new arrivals a good week or two to settle in, make themselves at home, and start feeding normally afterwards. For that reason, I suggest the hobbyist have a supply of live food on hand whenever acclimating new additions to his herd. The tiny red feeder shrimp from Hawaii (Halocaridina rubra) are ideal for this, but live Gammarus, ghost shrimp, or even adult brine shrimp will do. The live shrimp help them adjust during the initial acclimation period when you first introduce your seahorses to your tank. The live foods will give the new arrivals a head start, help them recover from shipping stress quickly, and get them through the difficult period of adjustment in tiptop condition.
Don’t worry about feeding your seahorses immediately after they arrive. Give them a good 24 hours to adjust and settle down first. After the adjustment period, go ahead and offer some carefully thawed Mysis to your seahorses each day. Many seahorses handle shipping and acclimation with ease and never miss a beat, gobbling up frozen Mysis from Day One. Others will need more time before they feel at home in their new surroundings, and may not feel comfortable enough to accept frozen Mysis from their keeper until a week or two has passed. So keep offering Mysis each day, but feed it sparingly at first and remove any uneaten Mysis after an hour or so. Once the seahorses that start eating the Mysis first have had their fill, add some live feeder shrimp for the others that are lagging behind.
Many times all the seahorses resume feeding on the frozen Mysis right away and the live red feeder shrimp aren’t needed; in that case, simply keep them on hand for use as occasional treats. They last indefinitely in a clean, aerated plastic bucket at room temperature with a pinch of flake food sprinkled in sparingly a few times a week.
Be patient with the ones that seem more reluctant to resume feeding on frozen Mysis. Don’t isolate them from the others, don’t pester them by persistently trying to target feed them at this point, and don’t keep dropping frozen shrimp on their heads! That can spook a high-strung seahorse and stress him out all the more, setting him back further. Just give them time and they will soon join the others, scarfing down frozen Mysis greedily again. This can sometimes take a couple of weeks. (Mature males often lag behind at first; for some reason, they seem to be more shy and retiring than females, which can be quite brazen at times. I suspect this is due to their parental duties — during the breeding season, pair-bonded males are ordinarily ALWAYS pregnant, and they can’t risk exposing their precious cargo to any more risk than absolutely necessary.) Make a note of the reluctant eaters; the ones that are slow to take frozen Mysis now may require target feeding later on.

(3) Be aware of secretive feeders and give them plenty of room at first.
It’s quite common for new arrivals to display shy, secretive behavior. I have found that some of my seahorses, especially newly acquired specimens, are reluctant to eat while they know they are being observed. That doesn’t mean they are starving themselves, however, just that they tend to feed in secret. Rather than feeding from your hand or gobbling up the Mysis when you first offer it, they will prey upon the natural fauna in the tank, slurping up copepods and amphipods from hiding, or snatch up leftover frozen Mysis when they think no one is looking. Some of the seahorses that don’t appear to be eating at first may actually be feeding on the sly.
When that’s the case, it’s best to back off a bit and leave the tank alone as much as possible for the time being. It’s okay to observe the tank discretely but try to avoid flat-nose syndrome, and keep feeding your other specimens as usual, of course, but don’t try to force the issue with the shy ones. Just leave them be, give the seahorses plenty of peace and quiet, and let the secretive feeders adjust to their new environment and get used to the daily routine at their own speed. Before too long, they’ll begin sneaking leftover Mysis when they think you’re not watching and feel safe. Once they feel at home, the shy specimens will start exploring their tank freely and displaying themselves openly. Before you know it, they’ll come to recognize you as their feeder and begin interacting with you at dinnertime. And from there, it’s just one short step until you have them literally eating from your fingers.

(4) Morning feedings are best.
The recommended feeding regimen is to provide each of your seahorses with 4-14 frozen Mysis shrimp daily, enriched with a good food supplement, and then to fast your seahorses entirely once a week. Some hobbyist prefer to give their seahorses two feedings a day, while others prefer to give them their quota of frozen Mysis in one big meal. As long as they get their fill, there is really no right or wrong way to go about this — just do whatever works bests for your seahorses and your schedule.
However, many hobbyists find that their seahorses feed best during the morning, so if you can only feed your seahorses once a day, try to make it a morning meal. Whether it’s their biological clocks, something built into their natural circadian rhythm, or whether they’re simply hungriest shortly after waking up, seahorses do seem to feed more aggressively in the morning, and hobbyists should try to accommodate them, if possible. Breakfast, it seems, is the most important meal of the day for our aquatic equines as well as ourselves.
If you can only manage one feeding a day, DO NOT make it an evening meal. The worst thing you can do is to feed your seahorses late in the day when there will likely still be leftovers remaining at lights out. The uneaten Mysis will begin decaying overnight and put your water quality at risk. Worse still, the next morning, when they are hungriest, your seahorses may discover the bacteria-laden Mysis and snap them up off the bottom. This is an excellent way to spread disease and make your seahorses sick. Feeding your seahorses early in the day, so they have plenty of time to clean up leftovers, is a good way to prevent this. An efficient clean-up crew of scavengers also helps.

(5) Use a feeding station.
Seahorses respond very well when they are fed at the same time and place each day. They quickly learn the routine and will come to recognize their keeper as the one who feeds them — the giver of gourmet delights! Once that happens, they will often beat you to the spot, gathering around their feeding station as soon as they see you approach.
In fact, the aquarist can easily condition his seahorses to come a running at feeding time. Before you open the aquarium cover, make a point of lightly tapping it a few times or rapping on it gently. The seahorses will quickly learn to associate the tapping with the mouthwatering morsels that follow, and before you know it, they will respond by gathering at the feeding station as if you were ringing the dinner bell.
To facilitate this process and make feeding them easier, choose a feeding station that’s convenient for you in a relatively uncluttered part of the aquarium, and give your seahorses their meal right there every day. The feeding station should have some convenient hitching posts situated nearby as well. Avoid using an area where currents might whisk the food away from the seahorses before they can eat it.
I know one hobbyist who uses a toadstool leather coral as his feeding station. He places the Mysis on the bowl-shaped top of the toadstool, which contains them nicely while his seahorses perch around the edges and scarf up the shrimp as if dining at a lunch counter.
Not everyone has a toadstool coral to serve as a natural feeding station, of course, but it’s easy to make your own lunch counter that will work just as well. Get a small Pyrex bowl or a similar shallow container made of clear glass or plastic (a large petri dish works great for this) and fill it about halfway with your tank substrate (Mike Kelly, pers. com.). Then sink the bowl into your sand bed until the substrate you placed in the bowl is level with the substrate in the tank (Mike Kelly, pers. com.). Leave the rim sticking up above the sand bed about a 1/2 to 3/4 of an inch or so (Mike Kelly, pers. com.). The clear glass rim of the bowl is transparent and virtually unnoticeable, so don’t worry that it will detract from the appearance of your display tank. Artfully position a few natural hitching posts around the bowl to provide your seahorses with a handy perch from which to snick up their dinner.
At feeding time, place the frozen Mysis on the sand or gravel inside the bowl. A long tube of clear plastic 1/2′ to 1′ in diameter facilitates this. The bottom of the tube is placed in the middle of the bowl and the enriched Mysis are then placed in the top of the tube, which guides them exactly where you want them as they sink. The rim sticking above the sand bed will then keep the food in place while your seahorses dine at their leisure. Afterwards, any leftovers are neatly contained, making cleanup a breeze!
Or you can always purchase a seahorse feeding station off the shelf, ready to go, as is. Artificial cup coral makes an attractive elevated "lunch counter" that does the job nicely. Elevated on a pedestal, the seahorses can perch around the edge of the cup, which contains the frozen shrimp nicely until eaten. The coral cups are very lifelike and make nifty ready-made feeding stations if positioned at a convenient (for you and your galloping gourmets) spot in your tank where currents won’t whisk the Mysis away.
Another handy item that makes a great ready-made feeding station for seahorses are the conical worm feeders designed for offering bloodworms and tubifex worms to fish. They may require a little modifying since many of them are designed to float. Depending on the type of feeder, you may have to perforate air filled chambers around the collar, weigh it down to submerge it, or cut the conical worm trap free from the rest of the feeder. Worm feeders come with a suction cup, so once you’ve overcome the buoyancy problem, they can be secured anywhere in the aquarium you want, and they work just as well with frozen Mysis as with worms. If you position the conical feeder where a slight current hits it, gently jostling and agitating the frozen Mysis inside, it is even more effective. The flow of water imparts a bit of movement to the frozen Mysis, causing it to twitch or swirl about just a bit periodically inside the feeder. This makes the thawed Mysis look all the more lifelike and quickly attracts the interest of the seahorses. They will gather around the feeder and snick up Mysis through the open top. The conical shape of these feeders contains the frozen Mysis even better than most other feeding stations.
Some hobbyists prefer a more natural looking, aesthetically pleasing feeding station, which they fashion themselves to suit their own tastes. They start with a piece of well-cured live rock that’s approximately the right size and shape, and painstakingly hollow out the center to form a shallow concave depression. This shallow bowl is fashioned by grinding it out, using an electrical moto-tool (available at any craft store or hardware store) with a carbide burr or sometimes even a shop grinder. Once the bowl has been hollowed out, a series of holes are then drilled around the circumference of this depression. Red, brown or purple Gracilaria, green Caulerpa and/or gorgonian branches are planted in these holes to create natural hitching posts. As the macroalgae takes hold and fills out, this produces an attractive feeding station that looks completely natural. It’s a great do-it-yourself project for the handy hobbyist.
An upturned clamshell also makes a nifty natural feeding station that fits in perfectly in your seahorses’ setup. Choose a colorful natural seashell for this, such as one valve of a Tridacna clam or perhaps a Lion’s Paw Scallop shell, and you have an attractive feeding station that’s perfectly appropriate for your tank. The concave interior of the bivalve shell acts as a shallow bowl to contain the frozen Mysis until it’s eaten, and unlike some feeding stations that look out of place and detract from the appearance of your tank, a seashell looks as natural as can be in a marine aquarium. My favorite for this type of feeding station is a medium-sized Abalone shell. The iridescent, opalescent colors of the upturned interior, with its magnificent polished surface of mother-of-pearl, are spectacular! An upturned abalone shell requires no further modification whatsoever, making it the ideal feeding station for the unhandy hobbyist who’s all thumbs.
Other aquarists reserve a small, transparent glass bowl or clear plastic receptacle for feeding their seahorses. They merely place the bowl or plastic container on the bottom of the tank at feeding time, add the enriched Mysis, and let their seahorses gather round and dine at their leisure as though eating from a feeding trough. A few hours later, the feeding container is removed, along with any leftovers. Quick and easy!
For more information, see my article in Conscientious Aquarist which explains exactly how to set up a feeding station and train your seahorses to use a in greater detail.. It’s available online at the following URL:

Click here: Seahorse Feeders
<<http://www.wetwebmedia.com/ca/volume_2/cav2i5/seahorse_feeders/seahorse_feeders.htm>&gt;

(6) Target feed your seahorses and remove uneaten leftovers promptly.
The individual personalities of seahorses naturally extend to their feeding habits. Some are aggressive feeders that will boldly snatch food from your fingers, while some are shy and secretive, feeding only when they think they’re not being observed. Some like to slurp up Mysis while it’s swirling through the water column, and some will only take Mysis off the bottom of the tank. Some are voracious pigs that greedily scarf up everything in sight, and some are slow, deliberate feeders that painstakingly examine every morsel of Mysis before they accept or reject it. Some eat like horses and some eat like birds. So how does the seahorse keeper make sure all his charges are getting enough to eat at mealtime? How does the hobbyist keep the aggressive eaters from scarfing up all the mouth-watering Mysis before the slower feeders get their fair share? And how can you keep active fishes and inverts with seahorses without the faster fishes gobbling up all the goodies before the slowpoke seahorses can grab a mouthful?
Target feeding is the answer. Target feeding just means offering a single piece of Mysis to one particular seahorse, and then watching to see whether or not the ‘horse you targeted actually eats the shrimp. Feeding each of your seahorses in turn that way makes it easy to keep track of exactly how much each of your specimens is eating.
There are many different ways to target feed seahorses. Most methods involve using a long utensil of some sort to wave the Mysis temptingly in front of the chosen seahorse; once you’re sure this has attracted his interest, the Mysis is released so it drifts down enticingly right before the seahorse’s snout. Most of the time, the seahorse will snatch it up as it drifts by or snap it up as soon as it hits the bottom.
A great number of utensils work well for target feeding. I’ve seen hobbyists use everything from chopsticks to extra long tweezers and hemostats or forceps to homemade pipettes fashioned from a length of rigid plastic tubing. As for myself, I prefer handfeeding when I target feed a particular seahorse.
But no doubt the all-time favorite implement for target feeding seahorses is the old-fashioned turkey baster. The old-fashioned ones with the glass barrels work best because the seahorses can see the Mysis inside the baster all the way as it moves down the barrel and out the tip. By exerting just the right amount of pressure on the bulb, great precision is possible when target feeding with a turkey baster. By squeezing and releasing the bulb ever so slightly, a skillful target feeder can keep a piece of Mysis dancing at the very tip of the baster indefinitely, and hold the tempting morsel right in front of the seahorse’s mouth as long as necessary. Or if the seahorse rejects the Mysis the first time it drifts by, a baster makes it easy to deftly suck up the shrimp from the bottom so it can be offered to the target again. In the same way, the baster makes it a simple matter to clean any remaining leftovers after a feeding session. (You’ll quickly discover the feeding tube is also indispensable for tapping away pesky fish and invertebrates that threaten to steal the tempting tidbit before an indecisive seahorse can snatch it up. And it’s great for tapping on the cover to ringing the dinner bell and summon the diners for their gourmet feast!)
In short, target feeding allows the hobbyist to assure that each of his seahorses gets enough to eat without overfeeding or underfeeding the tank. And it makes it possible to keep seahorses in a community tank with more active fishes that would ordinarily out-compete them for food, since the aquarist can personally deliver each mouthful to the seahorses while keeping more aggressive specimens at bay.
The key to keeping active specimens like firefish or compatible clownfish or cleaner shrimp successfully with seahorses is to feed the other fish and inverts with standard, off-the-shelf aquarium foods first, and once they’ve had their fill, then target feed the seahorses.

(7) Observe fast days and don’t overfeed.
One of the most common mistakes hobbyists make is to overfeed their seahorses. Any excess Mysis that’s not eaten within an hour or two of a feeding can become a threat to your seahorses. Either it will find its way into some inaccessible nook of the aquarium and begin to decay, degrading your water quality, or it may be noticed by a hungry seahorses hours later or perhaps even the next day, and eaten after bacteria have gone to work on it. The best way to avoid such problems is to target feed and remove leftovers promptly, as soon as you’re sure all the seahorses have had their fill. If you can only feed once a day, make it a morning meal before you leave for work, so the seahorses have the rest of the day to glean their leftovers. A good cleanup crew can also help by taking care of any uneaten morsels that slip past the aquarist.
It’s equally important to observe the once-a-week fast day. Fasting helps prevent any potential problems with hepatic lipidosis (fatty liver disease) and keeps your seahorses feeding aggressively rather than losing interest in frozen foods. The problem is that although fasting is very healthy for seahorses on a staple diet of enriched Mysis, it can be very hard on the hobbyist. Here’s how I described this dilemma in a recent aquarium magazine article (Giwojna, Jun. 2002):
"The only thing I don’t like about this extremely nutritious diet is the obligatory fast day. The problem with fasting is that my mustangs don’t seem to realize it’s good for them — that it’s absolutely in their own best interests, essential for their long-term health. Whenever I make an appearance on fast day, they insist on parading back and forth in front of the glass in their greeting colors, begging for a handout. Before my butt hits the upholstery, both of them will be dancing at the feeding station, impatiently awaiting their gourmet shrimp dinner. When it doesn’t materialize, they forlornly abandon their post at the lunch counter, and come up to stare at me through the front glass. When I still don’t take the hint, the female paces back and forth at the front, looking her brightest and most conspicuous, as though trying to attract my attention, while the male reverts to his drab everyday attire and dejectedly resumes his futile vigil at the feeding station. If not for their well-rounded cross-sections, one would think they were dying of hunger, making it difficult to resist their puppy-dog antics. Just sitting there ignoring them makes me feel like a first-class heel. Sheesh–talk about your guilt trips…Dang! I hate fast days." (Giwojna, Jun. 2002)

There you have it, Amanda — everything you need to know about feeding Ocean Rider seahorses. If you follow these feeding tips, it should help keep your next seahorses eating their best and you will soon find that keeping them well fed is fun and easy. Feeding time for my seahorses is always a high point in my day. They do appear amazingly like fire-breathing Dragons when they eat frozen Mysis — it looks for all the world like smoke is shooting out of their "ears" when they eat enriched Mysis, due to the pulverized particles they expel from their gills after slurping it up (Gilchrist, 2002).

Best of luck with your seahorses, Amanda! Your 40-gallon aquarium should make a fine seahorse setup and you are doing a lot of things right, including setting up a feeding station for your ponies. Be sure to enrich their frozen Mysis with Vibrance to bring up their brightest colors and consider switching to Osram Grolux fluorescent lighting, if possible, or else the combination of fluorescent tubes recommended by Paul Groves.

Here’s hoping your Sunbursts and Hippocampus reidi are soon shining forth in all their true glory!

Respectfully,
Pete Giwojna

Post edited by: Pete Giwojna, at: 2009/01/11 20:44

Dear Amanda:

It is common for residual levels of nitrite to remain in even well established marine aquaria. That’s okay, and not a cause for concern as long as we’re only talking trace amounts of the nitrite. The acceptable range for the nitrite is generally considered to be anything between 0.000 to 0.100 mg/L or ppm, but when you are consistently seeing levels in excess of 0.05 ppm, it’s advisable to find and correct the source of the residual nitrite.

In your case, a reading of 0.25 ppm nitrite is obviously above the acceptable level, but I’m not entirely certain that your reading is accurate. The color comparison test kits are simply not that precise, and you may want to take a sample of the aquarium water into one of your local fish stores so that they can evaluate the water quality for you using more sophisticated test equipment. That way, you can test the same water sample using your Aquarium Pharmaceuticals nitrate test kit and see if your reading agrees with the pet shop’s more accurate test results. If not, you may want to invest in a new test kit.

Also, if you’re using tap water to prepare the salt water when you make partial water changes, it’s quite possible that your tap water could itself be a source for the nitrite. Municipal water supplies often have chloramines that may affect the ammonia, nitrite, and nitrate readings in the aquarium when the tap water is used for water changes or to top off the tank when compensating for evaporation. So check the nitrite reading for your tap water to eliminate that as a potential source for the residual nitrite.

In the meantime, as long as the fish and invertebrates in your seahorse tank are not showing any harmful effects from the nitrites you have been detecting, I would not freak out about the situation. Your test kit may not be accurately reflecting the amount of nitrite that is present, and residual levels of nitrite are a much greater concern for reefkeepers with live corals than they are in a fish-only tank with a cleanup crew.

Your aquarium maintenance schedule and regimen of partial water changes are exemplary, so I don’t believe that uneaten frozen Mysis is at the root of this problem. In fact, if anything, your maintenance schedule may be a little too rigorous, Amanda. You want to clean or replace the pre-filter or mechanical filter that is straining out the particulate matter from your tank often so that it doesn’t get clogged and reduce the water flow through the filter, of course, but the activated carbon itself does not need to be replaced on a weekly basis. Your activated carbon should last for a good month before its chemisorption ability is significantly impaired and it needs to be replaced with fresh carbon.

The sponge filter will be become biologically active and house a large population of the beneficial nature find bacteria that provide biological filtration so it’s important to rinse and clean it in saltwater rather than fresh water. With a little practice, cleaning the foam filters properly is a snap. Simply immerse them in a bucket of saltwater and gently squeeze out the sponge until it’s clean and releases no more sediment or debris. (I use the saltwater I siphoned out of my aquarium when performing a water change for this, and clean my sponge filters whenever I change water.)

Here is some additional information of the water chemistry for a saltwater require that explains the basic parameters you should strive to maintain, Amanda:

Basic Water Quality Parameters.

Ammonia (NH3/NH4+):
Natural Seawater Value = 0.010 mg/L
Acceptable Range = 0.000 to 0.050 mg/L
Optimum Level = 0 at all times

Ammonia is highly toxic to both fish and invertebrates in even small amounts (> 0.05 mg/L or ppm). Causes of ammonia toxicity include: immature biofilter (new tank syndrome), impairment of the biological filtration due to antibiotics and other medications, overfeeding, overstocking and dead specimens that go undetected (Webber, 2004). Ammonia levels can also rise after the addition of new animals, after a water change, or following a heavy feeding. Any ammonia level above 0.05 mg/L is a cause for concern, and the source must be found and corrected immediately. Be sure to maintain a good schedule of water changes.

Nitrite (N02):
Natural Seawater Value = 0.010 mg/L
Acceptable Range = 0.000 to 0.100 mg/L
Optimum Level = 0 at all times

Nitrite is slightly less poisonous to fishes than ammonia, but deadly to many invertebrates at very small concentrations. Residual levels of nitrite are common in marine aquariums. Levels of 0.05 or less are of little concern in a fish-only aquarium. If the levels are higher than this, the source should be found and corrected immediately. Even trace amounts of nitrite can wreak havoc among the live corals and delicate invertebrates in a reef tank. High levels of nitrite result from the same causes as ammonia.

Nitrate (N03):
Natural Seawater Value = 0.050 mg/L
Acceptable Range = 0.000 to 20 mg/L
Optimum Level = below 10 mg/L in fish-only tanks; 0 mg/L in reef tanks.

Nitrate is the end product of the process of nitrification, formed during the Nitrogen Cycle by the oxidation of nitrite by aerobic bacteria. Nitrate is relatively nontoxic to fishes, but elevated levels (> 20 mg/L) are stressful to seahorses over the long term and promote the growth of nuisance algae. Reef invertebrates can be much more sensitive to nitrate, and concentrations as low as 0.06 mg/L can cause problems for symbiotic stony corals. Any level above 5.0 mg/L in reef aquariums is a reason for concern and should be corrected immediately. The nitrate level is a good indicator of water quality and rising levels of nitrates are an indication of deteriorating water quality. For best results, consider using live rock and/or a live sand bed (preferably situated in your sump) in conjunction with a good protein skimmer to help filter your seahorse setup. The skimmer will remove excess organic compounds before they enter the nitrogen cycle, and live rock and a deep sand bed will provide significant denitrification ability, all of which will help keep your nitrates down. Don’t overstock, don’t overfed, remove leftovers promptly (a good cleanup crew is useful here), grow and harvest macroalgae, practice good aquarium maintenance and maintain a sensible schedule for water changes.

pH:
Acceptable Range = 8.0 – 8.4 (typically fluctuates between 7.9 at night and 8.4 during the day)
Optimum Level = ~8.2 and stable.

The pH is a measurement of the alkalinity or acidity of aquarium water. A pH of 7 is considered to be "neutral," neither acid or alkaline, while pH levels above 7 are considered to be alkaline or "base," and pH levels below 7 are considered to be acidic. Marine aquaria need to maintain alkaline conditions at all times, and low pH (< 7.6) is especially detrimental to seahorses because it is conducive to Gas Bubble Disease. Normal daily fluctuations in pH are to be expected in the aquarium, and are generally gradual enough not to be stressful (Webber, 2004). Maintaining a sump or refugium with a reverse photoperiod to the main tank can eliminate these natural pH cycles. Regular partial water changes are the key to maintaining stable pH. Buffers can also help but the hobbyist should beware that excessive use of pH buffers may increase KH values to dangerously high levels.

Specific Gravity:
Acceptable Range = 1.020 -1.026
Optimum Level = 1.0245 for most seahorses.

The specific gravity measures the density of a your aquarium water relative to the density of distilled water, and aquarists use it to estimate the salinity of their aquarium water (Trevor-Jones, Dec. 2002). In effect, it’s one way to measure the saltiness of your tank, since the more salt that is dissolved in the water, the denser it becomes. This can also be done by measuring the total amount of dissolved solids in the water, which is expressed as the salinity in parts per thousand (ppt). Hobbyists must remember that constant evaporation of freshwater from the aquarium causes the salts to become more concentrated, which increases the specific gravity or salinity accordingly. Therefore, it is necessary to top off the tank with freshwater regularly in order to make up for evaporation and maintain the desired specific gravity. Seahorses tolerate a wide range of salinity very well and hyposalinity (specific gravity at 1.011-1.015) is often used to help rid them of ectoparasites.

Best of luck reducing the trace levels of nitrite in your seahorse tank to acceptable levels, Amanda! The problem may be as simple as a test kit that is a bit off or that your tap water itself contains residual amounts of nitrite.

Respectfully,
Pete Giwojna