Re:Lighting

Dear Chris:

It sounds like you have assembled the makings of an excellent seahorse setup! The 46-gallon bowfront aquarium is large enough to provide stability and a comfortable margin for error, along with plenty of room for large seahorses such as Sunbursts (Hippocampus erectus) to roam. You have plenty of live rock to provide additional stability and good biological filtration (both nitrification and denitrification) and a protein skimmer and a good canister filter for supplemental filtration and water movement. The canister filter will be able to provide mechanical and chemical filtration for the aquarium, as well as supplemental biological filtration. So it sounds like you’re off to a good start!

I’ll do my best to answer your questions one by one below, Chris:

1. I am looking to get a new light and add some corals to this tank when I get the horses(sunburst) and I am wondering if this light is okay or too much for them. An aquatic life 36 T5 HO.

You shouldn’t need a high output light for your seahorse tank, Chris. With seahorses, it’s best to limit yourself to soft corals which do not have the ability to sting the seahorses, and which can thrive with relatively low light levels and moderate water currents. An ordinary daylight fluorescent bulb will typically suffice for such soft corals. The bottom line when you are considering coral for your tank, you should select coral that do not need more than about 3-4 watts of light per gallon or ones requiring strong currents. Mushrooms, leathers and polyps come in many different colors and are very suitable for your seahorse tank and would make the best choices for coral in a seahorse tank. But it’s usually best to avoid stony corals, particularly LPS corals, which require strong lighting and pose a danger to our ponies by virtue of their stinging ability.

This is what I typically advise home hobbyists who want to keep seahorses in reef systems or with live corals, Clintos:

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Live corals are a different matter altogether, and you must observe some special precautions when selecting corals for a seahorse tank. Here are some suggestions regarding what specimens do well with seahorses and which should be avoided, if you will be keeping live corals with your ponies or maintaining a reef biotype for them:

Seahorse-Proofing the Reef Tank

When designing a reef tank that will include seahorses, one must anticipate the different ways they might be injured in such a setup and then take precautions to prevent them from coming to harm. The process of rendering your reef system seahorse safe is much like the measures new parents take to childproof their house when they are expecting their first child. Intake tubes for the filters should be shielded, siphon tubes should be equipped with filter baskets or screens, and so on…

For instance, when powerful water movement is combined with overflows, there is a risk that seahorses could become pinned against an overflow or even go over it (Delbeek, Oct. 2001). Therefore, in the seahorse reef, overflows must be baffled and/or screened off, or the water flow should be adjusted sufficiently to prevent that from happening.

Likewise, although seahorses have no problem with strong currents in the wild, in the confines of aquarium, it is possible for them to come in contact with stinging corals if they are struck by a sudden powerful wave or surge, or are overwhelmed by a strong, unexpected current (Delbeek, Oct. 2001). The hobbyist needs to take this into consideration when placing water returns and corals in the seahorse reef (Delbeek, Oct. 2001). If possible, keep the water currents steady and unvarying so the seahorses can establish holding areas in the sheltered spots and low flow zones without getting blindsided by unpredictable currents.

One good way to accommodate both the needs of corals that prefer brisk currents and the seahorse’s need for slack-water retreats is to create tall rock formations a foot or two down current from the strongest water flows to intercept and deflect or divert that strong flow of water, creating eddies and slack-water zones where there is relatively little water movement down current. Seahorses will hold in these low flow areas when they want to move away from the current, so it’s a good idea to position convenient hitching posts in the lee or down-current side of such formations..

Another excellent way to accomplish the same thing is to use small powerheads to create and direct current wherever needed. A properly positioned powerhead can thus bathe your prized Acropora formations in a brisk water stream precisely without generating too much water movement elsewhere in the aquarium. Just be aware that powerheads can become death traps for seahorses if their intakes are not properly shielded or screened off, and take the necessary precautions (Delbeek, Oct. 2001). Carefully conceal the intakes amidst the rockwork where they will be completely inaccessible to seahorses, otherwise shield them, or screen them off with a sponge prefilter.

In short, the hobbyist who wants to keep seahorses in a reef system must be willing to make some concessions and modifications to accommodate their special needs nonetheless. For example, the reef keeper must be willing to limit himself to corals and invertebrates that meet the following criteria:

1) Avoid any stinging animals with powerful nematocysts. This means fire corals (Millepora spp.) and anemones should be excluded from the seahorse reef, and any corals with polyps that feel sticky to the touch should be used with discretion and only after careful planning. When a seahorse brushes up against them or attempts to perch on them, the nematocysts or stinging cells of these animals can penetrate the seahorse’s skin and damage its integument. Needless to say, this causes pain and discomfort and can leave the seahorse vulnerable to secondary bacterial and fungal infections, which may take hold at the site of injury. Short polyped stony (SPS) corals are generally fine, but large polyped stony (LPS) corals should be regarded with caution, as discussed in more detail below.

2) Water movement and circulation must be managed as previously described. Corals that require powerful surge or overly strong water currents could overtax the limited swimming ability of Hippocampus unless slack water areas the seahorses can retreat to when needed are also provided.

3) The corals must be able to withstand being used as hitching posts by the seahorses from time to time; that is, they cannot be so delicate that having a seahorse’s grasping tail anchored around them could cause them any harm. For instance, soft corals may retract their polyps when a seahorse perches on them. This can be harmful to their health if it becomes a chronic problem, because many corals rely on their polyps to absorb light and convert it to energy via photosynthesis. Be sure to watch any soft corals and hermatypic corals to make sure they are not closed up for extended periods. Normally, they adjust to the seahorses’ presence and unwelcome attention after a while, and remain contracted only briefly after each contact. After repeated exposures to grasping tails, each such incident elicits a weaker response, so they tend to extend their polyps sooner and sooner after being disturbed (Delbeek, Oct. 2001).

4) Avoid Tridacna clams and similar bivalve mollusks. Sooner or later a seahorse will perch on them with its tail between the valves and the clam’s powerful adductor muscle will clamp down on it like a vise. At best this will be a very stressful experience for the unfortunate seahorse, since it can be the devil’s own business trying to persuade the stubborn mollusk to release its struggling victim! At worst, it can result in serious injury or permanent damage to the seahorses tail (Giwojna, unpublished text).

5) Beware of unwanted hitchhikers that may have come in on your live rock unbeknownst to you and which can harm seahorses, such as fireworms, mantis shrimp, or Aptasia rock anemones. When setting up a reef system for seahorses, it’s a wise precaution to pre-treat your live rock with a hypersaline bath to drive out such pests beforehand because they can be very difficult to remove or eradicate once they make themselves at home in your aquarium (Giwojna, unpublished text).

As long as the specimens you are considering for your seahorse reef satisfy these requirements, anything goes! Some of the good and bad candidates for such a reef system are discussed below:

Seahorse-Safe Corals

Soft corals have very little stinging ability and generally make good choices for a modified mini reef that will include seahorses (Delbeek, Oct. 2001). This includes most mushroom anemones (corallimorpharians). However, as Charles Delbeek cautions, "One notable exception is the elephant ear mushroom anemone (Amplexidiscus fenestrafer). This animal is an active feeder on small fish and will envelope them whole with its mantle then slowly digest them by extruding its digestive filaments into the space created. No small fish are safe with these animals in the tank (Delbeek, Oct. 2001).".

Hippocampus also does very well with zooanthids and colonial polyps in general. But the hobbyist must be sure to observe a couple of precautions when handling the zoanthids and placing them in your aquarium.

First and foremost, many of the commonly available Zooanthus (button polyps) and Palythoa (sea mats) species contain a very toxic substance in their mucous coat known as palytoxin, which is one of the most poisonous marine toxins ever discovered (Fatherree, 2004). Palytoxin can affect the heart, muscles, and nerves, resulting in paralysis or possibly even death, and many hobbyists have reported numbness, nausea and/or hallucinations after merely touching these corals (Fatherree, 2004). When you handle zoanthids and palythoans, you cannot help picking up some of their protective slime on your fingers, and so much as rubbing your eye, picking your nose, or a small cut on your finger can be enough to land you in the hospital. When handling Zooanthus are Palythoa species, it’s very important to wear disposable latex gloves, avoid touching your mouth or eyes, and carefully dispose of the gloves immediately afterwards (Fatherree, 2004).

Secondly, zoanthids and other soft corals such as mushrooms may wage border battles if you place them in close proximity to each other (and the zoanthids almost always lose out to the mushrooms in these skirmishes). So be sure to allow adequate space between the colonies. Some rapidly growing Zooanthus colonies can be aggressive to soft and stony corals alike as they rapidly spread over the rockwork, but in general they are quite peaceful, and you can always slow down their rate of growth by reducing the nutrient loading in the aquarium.

Other low light corals that should be suitable for a seahorse reef include genera such as Cynarina, Scolymia and Trachyphyllia, as well as non-photosynthetic gorgonians such as Subergorgia and Didogorgia, and perhaps wire corals such as Cirripathes spp. (Delbeek, Nov. 2001).. However, supplemental feedings of zooplankton may be required to maintain these corals in good health.

The hard or stony corals fall into two categories depending on the size of their polyps. The small polyped stony (SPS) corals have tiny polyps that extend out of minute openings in the stony skeleton, and generally have weak stings that should not pose a threat to seahorses. Depending on conditions in the tank, SPS corals such as Acropora, Montipora, Pocillipora, Porities, Seriatopora and Stylophora can be tried freely at your discretion (Delbeek, Oct. 2001).

The large polyped stony (LPS) corals, however, are generally best avoided altogether. These include genera such as Catalaphyllia, Cynarina, Euphyllia and Trachyphyllia that have large fleshy polyps which often have tentacles equipped with powerful stinging cells. The Euphyllia and Catalaphyllia have the most powerful nematocysts among the LPS corals, and can deliver stings that are stronger than most anemones (Delbeek, Oct. 2001).

Some of the soft corals and stony corals that generally do well with seahorses in a modified reef tank are listed below. (By no means is this intended to be a comprehensive list, but rather just a few examples of suitable corals to serve as general guidelines when stocking a reef tank that will house seahorses):

Finger Leather Coral (Lobophyton sp.)
Flower Tree Coral – Red / Orange, (Scleronephthya spp.)
aka: Scleronephthya Strawberry Coral, or Pink or Orange Cauliflower Coral
Christmas Tree Coral (Sphaerella spp.)
aka: the Medusa Coral, Snake Locks Coral, or French Tickler
Cauliflower Colt Coral (Cladiella sp.)
aka: Colt Coral, Soft Finger Leather Coral, Seaman’s Hands or Blushing Coral.
Toadstool Mushroom Leather Coral (Sarcophyton sp.)
aka: Sarcophyton Coral, Mushroom, Leather, or Trough Corals.
Bullseye Mushroom Coral (Rhodactis inchoata)
aka: Tonga Blue Mushroom, Small Elephant Ear Mushroom (rarely)
Clove Polyps (Clavularia sp.)
Stick Polyp (Parazoanthus swiftii)
Green Daisy Polyps (Clavularia sp.), Indonesia
Orange & Green Colony Button Polyps (Zooanthus sp.), Fiji
Pulsing Corals (Xenia spp.)
Red Ricordea (Ricordea sp.), Indonesia, occasionally Solomon Islands
Lavender Hairy Mushroom (Actinodiscus sp.), Tonga
Pimpled Mushroom (Discosoma sp.), Indonesia
Purple Gorgonians

For more information regarding seahorse-safe fish, corals, and other invertebrates, see Will Wooten’s online Compatibility Guide at the following URL:

http://www.seahorse.org/library/articles/tankmates.shtml

Lighting for a Seahorse Reef

If at all possible, metal halides should be avoided for a reef tank that will include seahorses. In addition to providing high-intensity lighting, the metal halides also tend to generate a lot of heat, and as you know, heat stress can be very detrimental to seahorses. Most of the subtropical/tropical seahorses do best at temperatures of around 73°F-75°F (23°C-24°C); so avoiding temperature spikes above 80°F (27°C) is very important. This can be very difficult to manage with metal halide lighting. 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." So it would be a shame to display brightly colored seahorses under metal halide lighting in a small, close system aquarium.

All things considered, power compact lighting is a better alternative for a seahorse reef. I prefer the power compacts because they allow me 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).

Basically, 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).

Although they are very costly, the new Solaris LED Illumination Systems are another good option for a seahorse reef. The Solaris LEDs can provide the spectrum of light and intensity needed by light-loving corals without the same concerns regarding overheating that make metal halides undesirable, and that’s a huge plus for the seahorse keeper. Aside from generating less heat, they also provide very considerable energy savings and the longevity of the LED is also superior to metal halide lamps. Best of all, the flexibility and adjustability of the Solaris LED Illumination System allows you to independently set the lights to duplicate sunrise, daylight, cloud cover, sunset, and even the lunar cycle. They certainly are very expensive, but they have some wonderful advantages over the conventional metal halide lighting, particularly for seahorses. However, because of the cost factor, I prefer PC lighting for a seahorse tank with live corals myself.

Of course, for seahorse keepers who do not have live corals in their corrals, standard fluorescent bulbs or tubes are more than adequate. For all intents and purposes, you really can’t go wrong no matter what lighting system you chose as long as you avoid overheating and provide both shaded areas where your seahorses can escape from light altogether and well-lit areas where they can bathe in the light as they please.

One good way to accomplish that is to keep the coral and inverts that require stronger lighting at one end of the tank, which is brightly illuminated, and keep the other end of the tank shaded to accommodate the seahorses, reserved for corals that don’t need high-intensity lamps. If need be, you can also provide shaded areas by positioning sections of aluminum foil atop your aquarium that are the right size and shape to cast shadows where you want them below. You will find your seahorses will move into and out of the light often, seeking the comfort level that suits them at the moment.
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2. How many sunbursts can I keep in this tank?

The recommended stocking density for large seahorses such as Mustangs and Sunbursts (Hippocampus erectus) is one pair per 10 gallons, Chris, meaning that a well-filtered 46-gallon aquarium such as yours can safely support up to 4 pairs or about 9 adult H. erectus individuals when it is fully stocked. But, of course, it’s always best to keep your aquarium under stocked to provide a comfortable margin for error while you are gaining practical experience working with your new seahorses. When you’re 46-gallon bowfront aquarium has had a chance to mature and become well-established, I would suggest starting out with 2 mated pair of Sunbursts. Assuming they do well under your care, you can gradually add more specimens and build up your herd over time. But it’s never a good idea to add too many seahorses to a newly established aquarium at one time. It’s better to increase your herd gradually and allow the biological filtration plenty of time to adjust to the increased bioload before you consider adding more new ponies.

3. Should I get a small powerhead for more GPH?

You generally want the filtration system and a seahorse tank to be able to turn over the entire volume of the aquarium about five times per hour, Chris, and it therefore sounds like you will easily achieve that with the Fluval 305 canister filter combined with the AquaC Remora protein skimmer. So I don’t feel an extra power head is going to be necessary to further increase your gph. This is normally what I advise home aquarists regarding the water flow in their seahorse tanks:

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Water Circulation for the Seahorse tank

Many seahorse keepers are overly conscious of the inactive life style and limited swimming ability of Hippocampus, and have adjusted their flow rates accordingly, resulting in undercirculated tanks with too little water movement. That’s a serious mistake for a small, close-system aquarium.

In actuality, seahorses prefer moderate water movement, including some areas of brisk current, providing there are also sheltered spots and some areas of relatively slack water they can move to when desired. Slack water means comparatively low flow, NOT stagnant conditions! As with any aquarium, avoid dead spots and stagnant areas in the seahorse tank at all costs (Giwojna, unpublished text).

Contrary to popular opinion, seahorses are quite effective swimmers that can hold their own in strong currents as long as sheltered areas are available (Delbeek, Oct. 2001). I have often discussed this matter with professional divers and collectors who regularly encounter seahorses in the ocean, and they report that the horses are often found where you would least expect them — well offshore and thriving in areas with powerful currents. For example, here is how Paul Baldassano, a commercial diver in New York who makes his living collecting sea urchins, describes the behavior of his local seahorses:

"In regard to seahorses in the wild, I occasionally see Hippocampus erectus in the wild while SCUBA diving but never in the places where they are supposed to be. I see them in the open sea far from shore and also in areas with large rocks and very strong currents. The last one I saw was in a channel off the south shore of Long Island New York in water about 12 feet deep. The current was so strong that I had to hold on to the rocks so as not to be swept away. This Hippocampus erectus was having no trouble staying there munching on the abundant plankton. Apparently they find places near the rocks where there is no current because as you know they are lousy swimmers. There is also a large population of seahorses in a similar area in another part of the New York shore, but I think it is best not to divulge that location for obvious reasons (Baldassano, pers. com.)."

Neil Garrick-Maidment, a very successful seahorse breeder in the UK, reports much the same thing, noting that seahorses in the wild seem to thrive amid strong currents:

"Whenever I have dived on Seahorse sites I have always been amazed by the currents and tides that this very fragile looking Seahorse lives in. We often find Seahorses in flat muddy/silt areas nowhere near rocks or weed. These areas are often scoured by strong currents and the Seahorses do well in them and seem completely unperturbed by the current (Garrick-Maidment, pers. com.). In setting up a tank for them I try to remember the feeling I had in those areas and replicate them. I have now started to use wave surge devices, so that the current in the tank, although strong (they seem to thrive in strong currents) varies in its direction (Garrick-Maidment, Jun. 2002)."

Kirk Strawn, who earned his Master of Science thesis studying Hippocampus zosterae in the field, echoes Neil’s thoughts on the matter:

"The aquarist is not giving his seahorses natural conditions when he keeps them in a still-water aquarium. In nature tidal currents, wind, and waves are usually mixing the well aerated surface film water with the deeper water."

Likewise, David Warland, a fish farmer and commercial seahorse breeder in Port Lincoln, Australia, reports he often finds Hippocampus abdominalis perching on the tuna net enclosures at the farm in deep water:

"The Horses that are around the farms have traveled vast distances over plain sand/mud to get to the farms, which are in at least 20 meters of water, and are miles from the nearest land or shallow water (Warland, pers. com.)."

And Jorge Gomezjurado, the Senior Aquarist at the National Aquarium in Baltimore, recommends the following when it comes to water movement:

"I personally believe that current and water dynamics are very important for Syngnathids. In nature they live in areas with active water movement.(i.e., tides in mangrove lagoons and estuaries, coral reefs, kelp forests, etc.). Why don’t we give them the same environmental conditions in captivity? Our small tanks (90 gallons) have large turnovers on an average of 5 gpm (or 300 gph). It is very important that the current is steady and directionally constant, which allows the animals to find a good spot to hold and they will not be pulling in different directions all the time."

Most seahorse keepers feel it’s best to keep the current steady and nonvarying so they can find slack-water areas and sheltered spots downcurrent to hold in when they want to get out of the current. The more brisk the water flow, the more important this becomes. However, in a large aquarium with low to moderate water movement, alternating currents should not present much of a problem, and would help to provide good circulation throughout the tank.

The point is that, as long as slack-water retreats are available, the greater seahorses can tolerate far more current than most folks suspect and good circulation is as important for a seahorse setup as any other aquarium. What seahorses lack as swimmers is not agility, but rather stamina (Evans, 1998). They can hold their own against strong currents, but not indefinitely, so low flow areas where they can move out of the current and hold when they want to rest must be provided in addition to good circulation.

For example, along with an external power filter, my seahorse setup also has a 200 gph powerhead with a sponge pre-filter positioned right near the top for surface agitation and extra water movement, with additional small powerheads used as needed to eliminate any dead spots along the substrate or behind the rockwork. I like to give my seahorses as much current as they can handle without getting blown around.

In short, if your filtration is not turning over the entire volume of the aquarium a MINIMUM of 5 times per hour, your seahorse setup is undercirculated. With a spray bar return raised above the surface of the water to diffuse the outflow, you can safely achieved much higher turnover rates without producing too much turbulence or current for seahorses. A waterfall return is another good way to diffuse the output from your filter, and also works well for seahorses. There will be an area of relatively vigorous water movement at one end of the aquarium underneath and nearby the waterfall, while the other end of the tank is a relatively low flow area. (By the same token, however, if the filtration system in your seahorse tank is turning over the entire volume of water much more than five times per hour, it may be too overpowering for the seahorses unless it is diffused by a spray bar or waterfall return.)

As with anything, too much of even a good thing can be undesirable, and too much current can overwhelm the limited swimming ability of Hippocampus. One indication that you may have too much water movement in your seahorse tank is if the seahorses are getting buffeted around by the currents, and whisked away uncontrollably when they tire of fighting the current. Or alternatively, they may stay perched in one place all the time and refuse to swim around and explore their tank for fear of getting swept away by the current if they relax their grip on their hitching posts. So you can get a pretty good gauge of how well the seahorses are able to cope with the water movement than their tank by observing how the current affects the swimming ability.

Likewise, if a mated pair of seahorses is consistently spilling eggs during the copulatory rise, that’s another pretty good indication that there may be too much turbulence or water movement in the upper reaches of their aquarium.

If the seahorses are having difficulty tracking their prey and eating because the current whisks the frozen Mysis past them too quickly to target it accurately and slurp it up, that’s another red flag. Often that situation can be corrected simply by adjusting the output from your filter to reduce the current during feeding time or turning it off altogether while the seahorses are eating.

But as long as your seahorses aren’t getting buffeted around, aren’t routinely dropping eggs during disrupted mating attempts, and aren’t having difficulty targeting their prey and eating, there’s really no such thing as too much water movement. In general, the stronger the water flow, the more important it is to keep the water currents steady and unvarying so the seahorses can establish holding areas in the sheltered spots and low-flow zones without getting blindsided by unpredictable currents. Just make sure your seahorses are not getting trapped against overflows and be sure to screen off the intakes for any powerheads. Powerheads can be switched off at feeding time, if necessary.

To sum up the above and quantify everything, you generally want the filtration system for seahorse tank to be able to turn over the entire volume of the aquarium about five times every hour in order to provide adequate circulation throughout the whole tank. So for the 46-gallon bowfront seahorse tank, Chris, the filtration system should put out about 250 gallons per hour in order to provide optimum conditions for the seahorses. If anything, you may need to tone down the output from the filter. Equipping your Fluval 305 canister filter with a spray bar return, if necessary, would be a good way to accomplish just that.

Since you’re in the process of setting up your seahorse tank at this time, Chris, I would like to invite you to participate in Ocean Rider’s training program for new seahorse keepers, if you haven’t already done so. It is quite comprehensive, completely free of charge, and should answer most all the questions you have regarding tank preparation and the care and keeping of Sunbursts. If you want to give it a try, just send me a quick e-mail off list ([email protected]) with your first and last name, and I will get you started out with the first lesson right away (it’s a correspondence course, conducted entirely via e-mail).

Best of luck with your new seahorse tank, Chris!

Respectfully,
Pete Giwojna