Hi, I’m new! Need some advice before starting.

Dear Katiee:

A 55-gallon aquarium with live rock and live sand and a good protein skimmer should make a fine home for a pair of Mustangs (Hippocampus erectus), and I would be happy to discuss the type of hitching posts and decor that is appropriate for a seahorse tank.

First of all, let me just say that since this is an established aquarium that has already been cycled, it’s appropriate to keep the protein skimmer operating continuously. It may not produce much skimmate or need emptying very often with such a light bioload, but protein skimmers should be operated 24/7 around the clock for best results. In addition to removing excess organics via foam fractionation, protein skimmers also help aerate and oxygenate the aquarium.

When aquascaping a seahorse tank, Katiee, the idea is to create a complex, natural environment for the seahorses with lots of shelter, well-shaded retreats, and convenient hitching posts. Seahorses prefer a fairly elaborate setup with lots of microhabitats that offers them plenty of cover and sight barriers so that they don’t feel vulnerable and exposed.

The plants and decorations can be real or synthetic, or a mixture of both. You can combine live plants with synthetic plants and live corals with artificial corals as you please in order to provide colorful, natural surroundings for your seahorses and create an aesthetically pleasing aquascape that will make your seahorses feel right at home.

A certain amount of complexity is desirable in a seahorse setup. For example, a tank with too few attachment sites and hitching posts is a stressful environment for seahorses, as is a sparsely decorated aquarium that leaves these secretive animals feeling vulnerable and exposed. Such sterile environments are commonplace when seahorses are being maintained under laboratory conditions. A Spartan setup facilitates feeding, water changes and maintenance, in general, but it can adversely affect the behavior of the inhabitants and may even prevent captive seahorses from breeding.

Hippocampus relies on camouflage and remaining hidden for its very survival. Seahorses can thus become distressed and agitated if their tank is too barren to provide adequate cover. This is particularly true during courtship and mating when the increased activity level and heightened coloration make them highly conspicuous and vulnerable, and breeding may be severely inhibited under these conditions.

A recent research project that studied the behavior of captive Cape seahorses (Hippocampus capensis) recently confirmed the need for a certain level of complexity in any setup for seahorses (Topps, 1999). The study found that seahorses display more "natural" behavior when they are provided with an elaborate, structured environment that includes a number of different microhabitats (Topps, 1999). These findings are another indication that a sparse setup with inadequate shelter can inhibit the behavior of captive seahorses.

So, as we’ve been discussing, your seahorse setup should therefore include plenty of hiding places and sight barriers such as live rock, real or artificial branching corals, and marine plants. It should be well planted and have lots of convenient hitching posts. This is what I usually advise hobbyists with regard to hitching posts:

Hitching Posts

When it comes to hitching posts and decorations, seahorses in general tend to prefer perches that are bigger in diameter over skinnier ones that are a bit more difficult to get a good grip on with their tails, but other than that, it’s very difficult to predict what they’ll go for. I have noticed that tree sponges and tube sponges — both the real thing (which are difficult to keep healthy) and the lifelike artificial versions (a much better choice for most tanks) — almost always seem to be particular favorites. Very often such sponges are bright red or yellow or brilliant orange in coloration, but I think it is the structure and texture of the sponges that attracts the seahorses more than the color.

Seahorses often tend to gravitate towards gorgonians, and the big purple gorgonians that are large in diameter are also usually very popular with seahorses. Otherwise, they seem to like genuine corals and synthetic corals about equally well, and the brightly colored formations (orange, red, or vivid yellow) usually produce better results than plain white corals.

Hitching posts for your seahorses can thus be either live or artificial marine sea grasses, algae and corals. If you decide to try an assortment of colorful artificial corals, seahorses often prefer red or orange pieces. Many hobbyists report good results using artificial finger sponges, staghorn coral, octopus coral and pillar coral in the appropriate colors to keep their seahorses looking their brightest. They look entirely natural and lifelike, with lots of branching projections that make great hitching posts for seahorses. Oh, and the artificial cup coral often makes a great ready-made feeding station! Living Color and the Signature Coral Corporation are the best sources for artificial corals, in my opinion.

Sea Garden synthetic aquarium plants also make good hitching posts for seahorses. The Sea Garden saltwater series of "Fancy Plants" are very realistic, completely safe for saltwater, and very easy to maintain. Just rinse them under warm running water before installation and periodically thereafter for cleaning. There’s a very nice selection of them available and seahorses can’t seem to tell the difference between them and the real thing.

For background decorations in a tall tank, I especially like the SeaGarden synthetic Sargassum plants because Hippocampus erectus is often associated with Sargassum in the wild and is famous for its rafting ability on mats of these plants. So it’s a natural biotype for erectus, and of course the Sargassum grows nice and tall, which is what we want for aquascaping the extra-tall tanks that are best suited for seahorses. I like to obtain one or more of the Large, Tall, and Extra Large examples of both the Sargassum fluitans (reddish brown in color) and the Sargassum platycarpum (green in coloration) and arrange them together across the back of the aquarium. They range in size from 12 to 24 inches in height, so I think if you group the tallest of the plants together, they should effectively conceal the filtration system and enhance the beauty of the aquarium, creating a colorful natural background with shades of green, brown, and red. They sway in the current just like the real plants and are very easy to clean and maintain. Just rinse them well under warm water when they need cleaning.

Before you put them in your aquarium, however, I recommend rinsing the Fancy Plants thoroughly under warm water and then soaking them in a bucket of clean tap water for several days, changing the water every day throughout this period to keep it clean and fresh. After the artificial plants have soaked for several days in this manner, you can give them another good rinse under warm water and then arrange them in your aquarium.

The SeaGarden Fancy Plants I mentioned above are available online from Drs. Foster and Smith at the following URL:

http://www.drsfostersmith.com/Product/Prod_Display.cfm?pcatid=9121&N=2004+113149

Macroalgae — Living Hitching Posts

For live hitching posts, I prefer decorative marine plants or macroalgae in a variety of shapes and colors and color — reds, golds, and yellows in addition to green varieties, some tall and feather, some short and bushy — to provide them with natural hitching posts and shelter. I like to start with a mixture of red and gold Gracilaria (Ogo) and artfully arrange them around a lush bed of assorted bright green Caulerpa. Any of the plumed (feathery) or long-bladed Caulerpa would be ideal for this, such as Caulerpa sertularioides, C. mexicana, C. ashmedii, C. serrulata or C. prolifera. But they may not be the best choice for tall tanks since none of these species will grow more than about 4-6 inches in height at the most.

Be sure to thin out the fast-growing Caulerpa regularly; when you remove the excess fronds, you’re exporting phosphates, nitrates and other nutrients from the tank, thereby helping to maintain good water quality, and thinning out the runners helps keep it from going sexual.
When "pruning" or thinning out 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 judiciously thinning out the colony otherwise prevents.

If you cannot obtain Caulerpa (it’s illegal in some coastal areas) or you’re simply concerned about your ability to maintain and control of Caulerpa properly, just use a different forms of macroalgae that grows less rapidly instead and you can get the same sort of benefits at relatively little risk. In that case, some of the other macroalge you may wish to consider are Gracilaria, Ulva, Chaetomorpha, and Chlorodesmis. Hawaiian Ogo (Gracilaria sp.) are bushy red-to-brown macros that do well under low light levels. Sea Lettuce (Ulva sp.) are deep green sheets of algae that do best under a little stronger lighting. Maiden’s Hair (Chlorodesmis sp.) are bright green tufts or clumps of very fine-bladed algal mats to grow attached to small rocks. All of these types of macroalgae are much less prolific and slower growing than Caulerpa. However, like all macroalgae, they should still be harvested periodically in order to export the excess nutrients they have consumed.

Aside from red and brown Gracilaria and the bright green Ulva and Maiden’s Hair, some seahorse keepers also like the Chaetomorpha turf algae or spaghetti algae, as it is also known. It can best be described as looking like the clumps of the colorful plastic grass we use to fill Easter baskets. Good on seven It is popular because it is slow growing and doesn’t require the kind of pruning that Caulerpa needs, and because it comes loaded with microfauna: miniature feather dusters, copepods and amphipods, tiny snails and micro stars. In short, Chaetomorpha is another interesting marine plant that can add some extra variety to a lush bed of macroalgae.

Seahorses also like live rock, particularly colorful pieces that are heavily overgrown with pinkish or purplish coralline algae. Aside from looking pretty, live rock also provides additional biological filtration (both nitrification and denitrification) for the aquarium and provides shelter and sight barriers that make the seahorses feel secure.

In short, special attention to the hitching posts you select when decorating your seahorse tank. Strive for bright reds, oranges, and yellows in anything your seahorses may adopt as a holdfast. These aquatic equines — especially the stallions — will often choose one particular hitching post as their home base and spend much of there time perched right there (think of your Dad hunkered down in his favorite easy chair in the den). Once they adopt a favorite base of operations like this, they will often proceed to change coloration to match their preferred resting spot. So you want to encourage them to adopt one of the more vivid pieces as a favorite holdfast whenever possible.

Aside from adding some appropriate hitching posts to create a natural setting with lots of microhabitats in your aquarium, you’ll also want to bolster your cleanup crew a little. As for your sanitation engineers, I prefer a cleanup crew consisting of a mixture of assorted snails and micro hermits (heavy on the snails but light on hermits) at a density of no more than 1-2 janitors per gallon at the most. (In your case, Katiee, you won’t need nearly that many scavengers if a pair of Mustangs will be the only fish in the aquarium.) The snail assortment 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 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

For best results, Astrea sp. snails should go in the tank as soon as the ammonia and nitrite levels are down to zero in order to keep nuisance algae from gaining a foothold in your tank. Introduced as soon as possible to a new aquarium, that has reached this cycling phase, Astrea snails effectively limit the development of all microalgae. In other words, they are good at eating diatoms, but will consume red slime and green algae as well.

But you must avoid predatory snails such as tulip snails, horse conchs, crown snails (Melanogena corona), and the venomous cone snails (Conus spp.), which can kill a human with a single sting from their harpoon like radula. Tulip snails, horse conchs, and crown conchs will hunt down and eat the other snails in your cleanup crew, whereas cone snails prey on small fishes in addition to presenting a deadly hazard to the aquarist.

For hermits, I like a combination of Dwarf Blue-leg (Clibanarius tricolor), Left-handed (Calcinus laevimanus), Mexican Red Legged Hermits (Clibanarius digueti) and above all, Scarlet Reef hermit crabs (Paguristes cadenati), which are my personal favorites.

The Scarlet Reef Hermit Crab (Paguristes cadenati) is a colorful micro-hermit that’s a harmless herbivore. So cannibalism isn’t a concern at all for these fellows, nor are they likely to develop a taste for escargot. As hermits go, most of the time the Scarlet Reefs are perfect little gentleman and attractive to boot. I even use them in my dwarf seahorse tanks. Best of all, they eat all kinds of algae, including nuisance algae such as red, green and brown slimes, as well as green hair algae.

If you’re going to have any hermits, stick with species like the above, which are known as micro hermits because they start out tiny and stay small. Avoid Anomura species of hermit crabs no matter how small they are, however, because they will kill Astraea snails to obtain their shells.

A mixture of the snails and micro hermits we have discussed will provide a very good balance of herbivores, omnivores, and detritivores that are all active scavengers and completely compatible with seahorses. They will clean up meatier leftovers such as frozen Mysis as well as helping to control nuisance algae.

With regard to the hermit crabs, there are a couple of other possible risks you should be aware of aside from the possibilities that the hermits could grow a large enough to be a threat to the seahorses.

For example, sometimes it works the other way around. Micro-hermit crabs are generally entertaining additions to an aquarium that do a great job as scavengers and get along great with seahorses, but over the years, I’ve had a few seahorses that were confirmed crab killers. These particular ponies were persistent hermit crab predators that specialized in plucking the hermits out of their shells and attacking their soft, unprotected abdomens, and they honed their skullduggery to a fine art. They were experts at extricating the crabs and would eat only their fleshy abdomens and discard the rest. Mind you, that was only a few individuals out of a great many Hippocampines, but I could never keep hermit crabs in the same tank with those specific seahorses.

On the other hand, sometimes it’s the micro-hermits that are the troublemakers. Most of the time, they coexist perfectly well with their fellow janitors in the cleanup crew. But I’ve had more than a few tiny hermits with a taste for escargot that persecuted snails mercilessly. These cold-blooded little assassins would kill the snails in order to appropriate their shells. Once they had dined on the former occupant, they would take up residence in their victim’s cleaned-out shell! It soon became clear that these killer crabs were driven not by hunger, but by the need for a new domicile. Once I realized they were house-hunting, I found I could curb their depredations but providing an assortment of small, empty seashells for the hermits to use. Colorful Nerite shells are ideal for this.

Since your 55-gallon aquarium is a well established tank, Katiee, you can also add a few large Peppermint Shrimp (Lysmata wurdemanni) and/or Scarlet Cleaner Shrimp or Skunk Cleaner Shrimp (Lysmata amboinensis) to complete your cleanup crew and add a touch of color and activity to the tank.

Peppermint shrimp (Lysmata wurdemanni) are a favorite with seahorse keepers because they eat Aiptasia rock anemones, and both the peppermints and Scarlet cleaner shrimp (Lysmata amboinensis) will perform another useful service by grooming the seahorses and cleaning them of ectoparasites. As an added bonus, they reproduce regularly in the aquarium, producing swarms of larval nauplii that the seahorses love to eat.

Just remember, it is important to select good-sized cleaner shrimp for your seahorse tank(s). Seahorses will actively hunt small cleaner shrimp and they are quite capable of killing shrimp that are far too big to swallow whole, so the cleaners need to be large enough that they are not regarded as potential prey.

Another thing to keep in mind when introducing cleaner shrimp to your aquarium is that they are more sensitive to water quality and rapid changes in pH, temperature, or salinity than fishes are, meaning the shrimp need to be acclimated more carefully and gradually. Whereas drip acclimation should be avoided for seahorses that have been on the shipping bag for 24 hours or more, it is the perfect way to acclimate delicate shrimp from your LFS. They will do best it drip acclimated to the new aquarium over a period of several hours to allow them to adjust to any differences in the water parameters very gradually.

There are also a number of seahorse-safe marine fish that make compatible tankmates for Mustangs which you can consider adding to your aquarium once you’ve gained a little more experience with the ponies, Katiee. When the time comes, I will be happy to discuss the possibilities in that regard.

For best results for seahorses, the home hobbyist should strive to maintain stable water conditions within the following aquarium parameters at all times:

Temperature = optimum 72°F-75°F (22°C-24°C).
Specific Gravity = range 1.022 – 1.026, optimum 1.0245
pH = 8.2 – 8.4
Ammonia = 0
Nitrite = 0
Nitrate = 0-20 ppm; optimum 0-10 ppm

Best of luck creating the optimum conditions for seahorses in your 55-gallon aquarium, Katiee.

Happy Trails!
Pete Giwojna