Dear Jay:

Dear Jay:

Yes, sir – a stable water temperature of 74°F would be excellent for both Hippocampus erectus and Hippocampus zosterae seahorses, so you can certainly consider plumbing the new 30-gallon MarineLand half-moon seahorse setup into your existing reef tank via a common sump. In fact, that arrangement could be quite beneficial, greatly increasing the total water volume of the aquarium system for the seahorses, which in turn would allow you to provide the ponies with much greater stability and better water quality than would otherwise be possible.

The large Hippocampus erectus in the tiny Hippocampus zosterae seahorses do have nearly identical aquarium requirements, and are therefore quite compatible in that regard, Jay. But I wouldn’t recommend keeping these two species together in a 30-gallon aquarium because their feeding requirements are quite different. The Hippocampus erectus will thrive on a staple diet of frozen Mysis, which the dwarf seahorses (Hippocampus zosterae) will be unable to eat. Rather, the Hippocampus zosterae will need large amounts of newly hatched brine shrimp or appropriately sized copepods on a daily basis in order to thrive, and the baby brine shrimp and larval copepods would be way too small to be of any interest to the much larger Hippocampus erectus seahorses.

Indeed, if you were to maintain an adequate feeding density of newly hatched brine shrimp for the sake of the Hippocampus zosterae, the clouds of baby brine shrimp would actually be irritating to the larger Hippocampus erectus, since they would tend to clog up the gills of the bigger ponies during normal respiration.

In short, if these would be your first seahorses, sir, then I would recommend concentrating on the Hippocampus erectus seahorses for now, such as Ocean Rider Mustangs and Sunbursts. They will be much easier to feed than the diminutive dwarf seahorses (Hippocampus zosterae), which are only about the size of your thumbnail when fully grown, meaning they would be all but lost in an aquarium as large as 30 gallons.

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

Their need for live foods.
(2) The small water volume of typical dwarf seahorse setups.
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 5-10 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. But if I had to choose between the two, Jay – which you should do when stocking your 30-gallon aquarium for best results – I would lean towards the larger Hippocampus erectus seahorses, which are much better suited for a tank of that size as well is much easier to feed.

Best of all, the Hippocampus erectus are now available in a number of different colors as a result of selective breeding at Ocean Rider. For instance, the Sunbursts can be either bright yellow or bright orange in coloration, whereas the Mustangs are available in both the usual dark brown or black which is the dominant coloration typical of wild Erectus, or as Silver Mustangs, which feature a much lighter, whitish background coloration, often overlaid with a fine pattern of parallel pinstripes.

Best of luck finding the perfect ponies for your new 30-gallon aquarium system once the tank has been cycled and the biological filtration has had a chance to mature and stabilize, Jay!

Respectfully,
Pete Giwojna, Ocean Rider Tech Support