IM confused

Dear fishlover:

Three factors make Pixies or dwarf unselected (H. zosterae) somewhat more demanding to keep than the larger breeds of seahorses such as Mustangs and Sunbursts (Hippocampus erectus):

(1) Their need for live foods.
(2) The small water volume of typical dwarf seahorse setups.
(3) Their susceptibility to aquarium hitchhikers and stinging animals (e.g., hydroids, Aiptasia).

Because of their small size and sedentary lifestyle, dwarf seahorses cannot be consistently trained to eat frozen foods without risking polluting the aquarium with uneaten food. As a result, the adults must be provided with copious amounts of newly-hatched brine shrimp (Artemia nauplii) at least twice a day and the fry must have access to bbs throughout the day.

This means maintaining a battery of brine shrimp hatcheries and hatching out large quantities of brine shrimp on a daily basis. If you are not proficient at hatching out brine shrimp or consider that to be too much of a hassle, then dwarf seahorses are not for you!

Because they are so terribly tiny — adult H. zosterae are only about the size of your thumbnail and half of that is tail — dwarf seahorses do best in small aquaria of 2 to 5 gallons to facilitate maintaining an adequate feeding density of bbs. Such a small volume of water is more susceptible to fluctuations in temperature, pH, and specific gravity than larger aquariums, and the water quality can also go downhill much faster in such small tanks than in large setups.

This means that dwarf seahorse keepers must practice diligent aquarium practices and an accelerated maintenance schedule in order to stay on top of water quality. As an example, water changes should be made weekly or biweekly, rather than monthly or bimonthly. This is not really onerous at all, since the water changes are so small (a fraction of a gallon to 1 or 2 gallons at most, depending on the size of the dwarf tank). It’s an easy matter to prepare and store a month’s worth of freshly mixed saltwater in advance, and I then find that I can perform a water change, vacuum of the bottom of my dwarf seahorse tank, and clean the sponge filters in no more than 5-10 minutes tops. But if the aquarist is not diligent about water changes and aquarium maintenance, dwarf seahorse setups can "crash" more easily than bigger, more stable aquariums with a larger volume of water.

The need for an accelerated maintenance schedule and daily feedings of live foods thus makes dwarf seahorses a bit more demanding to keep than the greater seahorses.

In addition, because of their diminutive dimensions, dwarf seahorses are susceptible to the stings from hydroids and Aiptasia rock anemones, which normally do not present a risk to the larger breeds of seahorses. Hydroids in particular are especially problematic for dwarves because once they find their way into a dwarf seahorse setup or nursery tank, the dreaded droids can explode to plague proportions very quickly because conditions are ideal for their growth: perfect temperatures, an abundance of planktonic prey that is renewed every few hours, and a complete absence of predators. As they proliferate and spread, they will soon begin to take a toll on the seahorse fry and even adult dwarfs can succumb to multiple stings or secondary infections that can set in at the site of a sting (Abbott, 2003).

The type of substrate — aragonite, black sand, crushed shell, coral sand, or a bare glass bottom — doesn’t seem to make much difference at all. It’s just that nursery tanks and dwarf seahorse tanks are perfect environments for culturing hydroids, and once they find their way into such a system they go forth and multiply with a vengeance. So unless dwarf seahorse keepers take special precautions, they can find themselves waging a losing battle with an infestation of hydroids, and that’s something that hobbyists who keep larger seahorses simply never need to be concerned about.

However, dwarf seahorses are widely considered by far the easiest seahorses of all to raise. They are prolific, breed readily in groups, and produce large, benthic fry that accept newly-hatched brine shrimp as their first food and reach maturity in as little as three months. They are the least expensive of all the seahorses to own and a dwarf seahorse aquarium can be set up far more economically than a system for keeping the larger seahorse species.

Dwarf seahorses are therefore ideal for breeders and anyone operating on a shoestring budget. Pint-sized and prolific, these pigmy ponies are the perfect pick for anyone primarily interested in rearing or for any seahorse keepers who can’t afford to devote too much money or space to their hobby. Hippocampus zosterae is the best choice for the novice who wants to learn more about keeping and breeding seahorses before moving on to the big boys. More budding seahorse keepers have cut their teeth on dwarves than all the other seahorses put together. H. zosterae is the right pick for newbies who would like to try their hand with seahorses for a modest investment, or for hobbyists with a tight budget, or aquarists looking for captive-bred seahorses that are a snap to breed and a breeze to raise, or anyone captivated by keeping tiny elfin creatures no bigger than your thumbnail.

All things considered, I feel that the many advantages of keeping dwarf seahorses far outweigh the drawbacks we have outlined above.

Feeding Pixies/Dwarf Seahorses

Pixies or dwarf seahorses do not need to be fed any particular time of day, but it’s best to provide them with copious amounts of newly-hatched brine shrimp (Artemia nauplii) at least twice a day. A feeding schedule that works well for most folks who keep Pixies is to give them a heavy feeding of baby brine shrimp before they leave for work or school in the morning, and then another heavy feeding when they return from work or school in the afternoon.

No, sir, you do not fast Pixies one day a week. That’s only for larger breeds of seahorses that are receiving a liquid-rich staple diet of enriched frozen Mysis. Dwarf seahorses feed on newly-hatched brine shrimp throughout their lives and should never be fasted.

Newborn dwarf seahorses eat the same food as the adults and can be raised right alongside their parents in the same aquarium if need be, but for best results, you need to alter your feeding regimen and maintenance schedule somewhat when you are raising the fry. For example, the adults do well with two feedings a day, but the babies require more frequent feeding and will do better if they are fed 3-5 times a day. Ideally, newly-hatched brawling shrimp should be available to the young at all times so they can feed at their leisure throughout the day. And when you are feeding more often, you will also need to perform more frequent water changes and siphon fecal pellets up regularly in order to maintain water quality, as discussed below.

Cannibalism is unknown in H. zosterae, and one of the neat things about them is that the fry can be reared in the main tank right alongside their parents since the newborns eat the same foods as the adults. However, to maximize growth and improve survivorship, the fry should be reared in a separate nursery tank where the hobbyist can maintain better control over their feeding, growth and development (Bull and Mitchell, 2002, p57). A basic benthic nursery with sponge filters works great for this and can be set up in much the same way as the adult tanks.

More frequent maintenance is required for the nurseries, however. With heavy, continuous feedings in such a small volume of water, regular siphoning is necessary to maintain water quality (Bull and Mitchell, 2002, p57). Fecal pellets and debris should be siphoned from the bare-bottomed nurseries at least twice a day with the deficit made up with new seawater (Bull and Mitchell, 2002, p57). The sponge filters must also be cleaned often as described previously.

The benthic fry thrive on newly hatched brine shrimp (Artemia nauplii) with small, frequent feedings that provide live prey throughout the day. They seek out hitching posts from birth, meaning the fry rarely gulp air, floaters and surface huggers are virtually nonexistent, and they are largely immune from the buoyancy problems that so often plague pelagic seahorse fry.

Experienced aquarists often achieve good success rates (better than 20% survival) in rearing H. zosterae to adults using these simple methods (Bull and Mitchell, 2002, p57).

Further details on feeding and breeding and rearing your Pixies are available in Alisa Abbott’s guidebook titled Complete Guide to Dwarf Seahorses in the Aquarium.

Tankmates for Dwarf Seahorses

Although their small size does indeed limit the suitable tankmates that can be kept with dwarf seahorses, I have found small pipefish do well with H. zosterae. I have a pair of small Gulf Pipefish (Syngnathus sp.) from Florida in my dwarf tank, which add a lot of interest to the aquarium because their behavior is so different from the dwarves (Giwojna, 2005). For example, when they’re just trying to blend into their surroundings, the pipes orient themselves vertically, heads up and tails down, and sidle up alongside a fake gorgonian or a tall clump of sea cactus, imitating one of the branches. It’s not a bad bit of camouflage, and once in a while one of the seahorses perches on a pipefish by mistake and gets taken for a wild ride, like a bareback bronco rider at a rodeo.

But when they’re hunting, the pipes slip into the beds of Caulerpa horizontally, and launch themselves like torpedoes at passing prey (Giwojna, 2005). Unlike the seahorses, which prefer to wait for their prey to come to them, the pipes dart out from hiding and snatch up brine shrimp right and left. It’s amazing how much faster and more agile they are than the pigmy ponies. At feeding time, the pipes go blasting around the tank like little guided missiles. Fortunately, with just two pipefish in the tank, they can’t make a serious dent in the swarms of Artemia.

Like the seahorses, these pipefish are livebearers and give birth to independent babies that are miniature replicas of themselves, except that the newborn pipes are totally transparent (Giwojna, 2005). They look like glass splinters or tiny transparent threads. Although I never made a serious attempt to raise them, a number of them survived for several weeks when left to their own resources in the dwarf tank. They were very good at concealing themselves amid the macroalgae, and especially liked to take refuge amongst the "bristles" of my Merman’s Shaving Brushes. The dwarf seahorses have no interest in them whatsoever, but I strongly suspect the parent pipes are cannibals. All in all, Gulf pipefish are inexpensive and entertaining additions to my dwarf seahorse setup.

For a nice splash of added color and natural beauty, I also like to add an assortment of Feather Dusters (Sabellastatre magnifica and Sabella sp.) amidst my beds of macroalgae. They are the brightly colored flowers blooming among all the greenery of this underwater garden. Feather Dusters are exotic, very showy, entirely harmless, relatively inexpensive, and completely compatible with dwarf seahorses (Giwojna, 2005). They are filter feeders and seem to eat the same newly hatched brine shrimp as dwarf seahorses, but they do best when fed phytoplankton (or commercial food preparations designed for filter-feeding invertebrates) with a baster from time to time.

The Lettuce Nudibranch (Elysia crispata, formerly known as Tridachia crispata, and still usually sold under that name) is another showy, totally innocuous invertebrate that’s a perfect choice for a dwarf seahorse companion. It is green with lavender spots and is covered with extravagant frills and ruffles that look like flower petals on an exotic orchid, but in fact they are the ruffled flaps of tissue (parapodia) that outline each side of the back of this two inch sea slug that lives in the waters of the Caribbean and Florida Keys (Giwojna, 2005). It’s an algae eater that dineson macroalgae such as Caulerpa sertularioides and is one of the few nudibranchs that do well in the aquarium, particularly a dwarf tank with a lush bed of Caulerpa (Giwojna, 2005).

I also have a handful of Volcano shrimp or Hawaiian red feeder shrimp (Halocaridina rubra) in the tank, not as food for the dwarf seahorses but rather as their tankmates. These colorful little saltwater shrimp resemble miniature peppermint shrimp, and usually do well with dwarves because of their size. They are too big to be eaten by the seahorses and too small to be any threat to them, and as an added bonus, they will produce larval shrimp that are perfect treats for the ponies. They are omnivores that do a fair job of scavenging and complement the regular clean-up crew nicely (Giwojna, 2005).

Along with the Volcano shrimp, Nassarius snails and Scarlet Reef hermit crabs (Paguristes cadenati) can serve as the cornerstones of the clean-up crew for dwarf seahorse tanks. The Scarlet Reef micro-hermits are colorful and interesting in their own right, and these harmless herbivores are the only hermit crabs I trust with my dwarf seahorses. A few of the colorful Scarlet Reef crabs make nice additions for a dwarf seahorse tank, as do the Nassarius snails, which are very active, efficient scavengers that handle the meatier leftovers.

Also worth considering are the tiny brittle starfish commonly known as Micro-Stars and often marketed as aquarium scavengers or sanitation engineers under that name. They start small and stay small, with a leg span that never exceeds the diameter of a 25-cent piece even when they are fully grown (most of these miniature brittle stars cannot span a 5-cent piece). Their legs are often attractively banded and they are very active and agile scavengers, moving more like miniature octopus that slowpoke sea stars. The micro-stars are fascinating in their own right, but it’s best to limit yourself to one or two of them, since they reproduce very quickly when conditions are to their liking.

Those are a few possible tankmates you can consider for your dwarf seahorse setup, fishlover.

Natural Habitat — how to make your dwarf seahorses feel at home!

H. zosterae is restricted to seagrass microhabitats in shallow water, and is typically found living in association with the seagrass Zostera (Bull and Mitchell, 2002, p56), for which the species is named.

The dwarf seahorse resides in shallow grass flats amidst Zostera and other seagrass and is also known for its rafting ability, commonly being found in mats of floating Sargassum.

These tiny seahorses are tough as nails, a legacy of their shallow, inshore environment in which the water conditions typically range from 43 F to 98 F (6 C – 37 C) and from marine to brackish (40% fresh water) during the seasons. They tolerate extremes that would be fatal to most other fishes and can adapt to a wide range of temperatures and salinity in the aquarium, but they are most common in bays during periods of high salinity and prefer the specific gravity to be maintained in the low normal range (1.019-1.022). They are diurnal seahorse that are active by day, and their aquarium should be lighted at least 12 hours a day since their breeding season is determined by day length (they stop reproducing when there is less than 12 hours of daylight) (Strawn 1954).

Since seagrass meadows are the home for dwarf seahorses in the wild, the best thing you can do to make them feel right at home in your aquarium is to provide them with lots of macroalgae and marine plants that closely simulate their natural habitat.

For example, a lush bed of assorted Caulerpa dominates the rear third of my current dwarf tank, completely concealing the sponge filters. The Caulerpa consists of various long-bladed and plumed or feathery varieties such as Caulerpa sertularioides, Caulerpa mexicana, Caulerpa ashmedii, Caulerpa serrulata and Caulerpa prolifera. The center of the tank is aquascaped with more macros — mostly red and gold species of Gracilaria (Hawaiian Ogo), plus a seahorse tree centerpiece and yet more Caulerpa. Other decorative macros are arranged in the foreground of the aquarium where the light is brightest: a cluster of Merman’s Shaving Brushes (Penicillus capitatus) and a stand of Halimeda sea cactus, interspersed with Udotea palmate fans. The result is a colorful macroalgae garden with a very nice contrast of colors (reds, yellows, greens, and brown) and interesting shapes. A tank heavily planted with macros such as these is a lovely sight and mimics the dwarf seahorse’s natural seagrass habitat well.

As an added benefit, the macroalgae act as an excellent form of natural filtration, supplementing the sponge filters, and reducing the available levels of phosphates and nitrites/nitrates. When we prune and trim back the fast-growing Caulerpa regularly and remove the clippings, we’re actually exporting phosphates, nitrates and other nutrients from the tank, thereby helping to maintain good water quality.

Best wishes with all your fishes, Carlos! When setting up your dwarf seahorse tank, just be patient — scads more information on the care and keeping of H. zosterae is on its way to you off list via your personal e-mail address.

Happy Trails!
Pete Giwojna