Re:Stocking first Seahorse tank…

Dear Reverend:

With your background as a reefer, I’m sure you’ll be very successful keeping seahorses, sir. Thus far, your 29-gallon aquarium sounds like a superb setup for Mustangs and Sunbursts (Hippocampus erectus)! The DLSB and live rock should provide efficient biological filtration, power compacts with automatic timers are my preferred method of lighting for a seahorse tank that will include soft corals such as mushrooms, zoanthids, and leathers, and you have equipped the tank a good protein skimmer. The seahorses are sure to appreciate the red grape Caulerpa and blade Caulerpa and should thrive in an aquarium swarming with assorted ‘pods. However, I do have a few suggestions for you to keep in mind in order to achieve the best possible results.

For one thing, although your zoanthids are seahorse safe, I want to remind you to handle them with all due care. As I am sure your already aware, it’s very important to observe a couple of precautions when you’re handling the zoanthids and placing them in your aquarium.

First of all, 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.

Secondly, "Zooanthus and Palythoa both contain very toxic chemicals, that can be dangerous to both reef inhabitants and humans. The most well known is Palytoxin, which has been documented as one of the most poisonous marine toxins known (Mereish et al, 1991). Palytoxin can affect the heart, muscles, and nerves leaving its victim in paralysis, and possibly death. Because of the toxin, you should never handle Zoanthus or Palythoa with open wounds, nor should you touch your mouth or eyes after handling the species. (We recommend the use of disposable latex gloves) When propagating either of the species, it is critical to remember that the slightest rub of an itchy eye, or even a small cut from a hang nail, might be enough to land you in the hospital. In the aquarium, some rapid growing Zoanthus colonies can be aggressive to stony and soft corals, but in general, they are very peaceful, and you can slow the growth rate by the controlling the overall nutrient load of your tank."

So be sure to use protective gloves and observe the necessary precautions when you’re working with the zoos, Reverend.

If possible, I would also suggest adjusting the timers on your power compacts to provide your seahorses with a simulated dusk and dawn, as discussed below:

When ut 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 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 — from metal halides to power compacts or VHO lighting to daylight fluorescent tubes to ambient room light — providing shaded areas are available to them and overheating does not become a problem.

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).

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).

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 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.

Caulerpa and macroalgae in general do an excellent job of simulating the seagrass beds that are the natural habitat of many seahorses. Just be sure to prune and trim back the fast-growing Caulerpa regularly; when you remove the clippings, you’re exporting phosphates, nitrates and other nutrients from the tank, thereby helping to maintain good water quality, and pruning the runners helps keep it from going sexual.

When pruning or trimming back macroalgae, take care not to actually cut it. Remember, you’re not pruning hedges or trimming trees — the idea is to carefully pull up and remove continuous, unbroken fronds. Simply thin out the colony of excess strands, gently plucking up convenient fronds that can be readily removed intact. A little breakage is fine, but cutting or breaking too many strands will result in leaching undesirable substances into the aquarium water as the Caulerpa’s lifeblood drains away. Too much cutting or breaking can thus sap the colony’s strength and cause die offs or trigger the dreaded vegetative events that judicious pruning otherwise prevents.

In addition to the Caulerpa, you may also want to consider some red or gold Ogo (Gracilaria spp.) to add to the decor of your seahorse setup. The Gracilaria are less prone to vegetative events and generally less aggressive than the Caulerpa, which may exude chemicals that can inhibit the growth of other macroalge and certain corals under certain circumstances.

Before we move on, I would also like to emphasize one important point regarding feeding seahorses in a tank like yours, Reverend. Whether it is a SHOWLR tank, a modified minireef, a seagrass system or a mangrove biotype, a well-designed seahorse setup is an elaborate environment. A certain level of complexity is necessary in order to assure that our seahorses feel secure and behave naturally (Topps, 1999), and to provide our ponies with plenty of hitching posts and shelter, as well as enough sight barriers to assure them a little privacy when they feel the need to be alone. Their homemade habitat may thus take the form of a labyrinth of live rock, an intricate arrangement of corals and gorgonians, a well-planted bed of seagrass or macroalgae, or a full-fledged reef face. When feeding seahorses in such intricate surroundings, the worst thing you can do is to scatter a handful of frozen Mysis throughout the tank to be dispersed by the currents and hope that the hungry horses can track it all down. Inevitably some of the frozen food will be swept away and lodge in isolated nooks and crannies where the seahorses cannot get it. There it will begin to decompose and impair your water quality, which is why ammonia spikes are common after a heavy feeding. Or it may be wafted out into the open again later on and eaten after it has gone bad. Either outcome can lead to dire problems.

The best way to prevent such problems is by target feeding your seahorses or training them to use a feeding station, as discussed below:

Feeding Stations

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;

Target Feeding

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 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.

In addition, it’s a good idea to install an efficient cleanup crew in a seahorse tank to help clean up any leftovers. A stocking density of up to 1-2 janitors per gallon is appropriate for a seahorse setup that includes lots of live rock and live corals. The cornerstone of the cleanup crew in most seahorse setups is an assortment of snails. These may include bumble bee snails, trocha snails, margaritas, Astrea and Cerith snails, red foot Moon snails, etc., but especially Nassarius snails.

Nassarius snails are terrific detritivores/omnivores and amazingly active for snails. They’ll bury themselves until they detect the scent of something edible, and then erupt from the sand and charge out to clean it up.

A varied assortment of snails is very desirable because different types of snails have different habits, seek out various microhabitats within the aquarium, and prefer to eat different things. Some are herbivores that feed on microalgae, and some of the herbivorous snails prefer to graze on it from the substrate, others like to to clean it from the rocks, and still others love to scrape algae off the aquarium glass. Furthermore, the different herbivorous snails tend to specialize on different types of microalgae and have definite preferences as to the types of algae they will eat, so it’s important to have a nice variety of snails that cover all the bases in that regard. It’s equally important to include some omnivorous snails in your assortment, which will go after meaty leftovers, along with the vegetarians. And you’ll want to have plenty of detritivores, too, which will feed on detritus and decaying organic matter in the aquarium

With regard to the volcano shrimp from Hawaii, I know a great many hobbyists who have gradually adjusted the red feeder shrimp to full strength saltwater without any problems whatsoever. The volcano shrimp or red feeder shrimp (Halocaridina rubra) seem to do fine at normal aquarium salinities indefinitely and I believe they do reproduce under those conditions, albeit very slowly. You will find the red feeder shrimp (Halocaridina rubra) to be easy to keep and relatively undemanding to culture, although their numbers build up very gradually due to their naturally slow rate of reproduction.

Red feeder shrimp or volcano shrimp, as they are sometimes known, prefer brackish conditions and breed best at reduced salinity (1.0145-1.0168) but they adapt well to full strength saltwater and will survive indefinitely is a marine aquarium. They are a perfect "feed-and-forget" treat for large seahorses! As a rule they don’t need a great deal of room. The size of the tank you’ll need depends on the number of shrimp your dealing with and whether you want to maintain and ongoing culture or simple keep them alive until needed. A 5-10 gallon tank will generally suffice for 500-600 of these shrimp and biological filtration of some sort is desirable for keeping them long term. A simple sponge filter will do.

Here is some additional information about these shrimp that may be of interest to those of you who are interested in keeping or culturing these colorful little crustaceans:

RED FEEDER SHRIMP from Hawaii (Halocaridina rubra)

Pros:
* Excellent nutritional value
* Irresistible to all the greater seahorses.
* Feed-and-Forget — lasts forever in saltwater!
* Easy to enrich.
* Simple to gut-load.
* Can be cultured using simple techniques and the most basic setups.

Cons:
* Reproduces slowly; difficult to build up a large population.

Collecting Tips:
None.

Culture Instructions:
Specific gravity: 1.0145-1.0168; pH: 8.0-8.3
Temperature: 68 degrees F – 73 degrees F (20 degrees C – 23 degrees C)

These fabulous little feeder shrimp can be kept indefinitely in a spare 2-10 gallon tank, or even a clean, plastic bucket, that has been filled with clean saltwater and equipped with an airstone for aeration. Neither a heater nor a fancy filtration system is required. They thrive at room temp and reduced salinity (1.015-1.016), and all they require is an airstone (or a simple air-operated foam filter at most) to keep the water oxygenated, with perhaps a little coral rubble as substrate and a clump or two of macroalgae (sea lettuce, Ogo, Gracilaria) to shelter in. They’re easy to feed — they feed primarily on algal mats and bacteria — but they will accept vegetable-based flake foods and pellets such as various Spirulina products. They are filter feeders and can also be fed with yeast or commercially prepared foods for filter-feeding invertebrates. Many people find an easy way to feed them is to place a small piece of algae-encrusted live rock in their holding tank; once they clean it off, simply replace it with a new piece of algae rock. But if you want to culture them, I’d recommend ordering the special shrimp food formulated just for them when you order your feeder shrimp from Hawaii. It’s designed to meet all their needs and requirements.

Comments:

These tiny red feeder shrimp (Halocaridina rubra) are native to Hawaii where they inhabit underground lava tubes. Brackish pools collect in the cracks, crevices and depressions in the lava below the water table, thus forming the habitat for the shrimp. The brackish water that fills these pools consists of intrusive seawater diluted by freshwater that percolates downward. Because of their lava-tube habit, they are sometimes called Hawaiian Volcano Shrimp.

Native Hawaiians call them Opa’e-ula, and they are unique among the several different species anchialine pond shrimp in being small, social, herbivorous shrimp that feed mainly on algae and bacteria. They are known to feed on insects that drown in the lava tubes. When conditions are favorable, they may feed en masse at the surface in swarms of countless individuals that turn the water red.

Halocaridina rubra look like miniature, bite-size Peppermint Shrimp, and all seahorses save the miniature species go absolutely nuts for them! They are very nutritious and eat a varied, omnivorous diet. They are perfect for seahorses in every way.

Unfortunately, it is very difficult to culture these shrimp in any quantity, since they reproduce slowly and the females only carry 12 to 14 eggs. They spawn but 4 or 5 times and produce an average of only 5-10 larvae per spawn. The larvae hatch as free-swimming, yolked zoeae after a brooding period of 38 days. Larval development is abbreviated with four zoeal stages and one megalopial stage occurring before they reach the first juvenile stage. Duration of the larval stages in the aquarium is 24 to 27 days at 22 to 23 degrees C.

Like other shrimp, it is the complicated larval developmental period they undergo, with multiple zoea and megalops stages, that makes the larvae difficult to raise, Reverend. You certainly may keep them in a refuge after acclimating them to full strength seawater, sir, but it’s difficult for the home hobbyists to maintain a self-sustaining colony of them under any circumstances.

In summation, your 29-gallon seahorse setup should certainly be able to sustain a pair of Mustangs and they pair of Sunburst (Hippocampus erectus). Many hobbyists find jawfish to be fascinating tankmates for their seahorses, and the deep sand bed in your tank will be perfect for the jawfish to burrow in, so all should go well as long as you quarantine the jawfish to make sure it is healthy before introducing it to your seahorse tank.

Good luck with your new seahorse setup, sir! Best wishes with all your fishes (and invertebrates), Reverend!

Happy Trails!
Pete Giwojna