tank requirments

Dear Sir:

Howdy, Josh! Welcome to the Club!

Unless you will be keeping one of the miniature breeds of farm-raised seahorses, such as Hippocampus zosterae, H. breviceps, or H. tuberculatus, it’s best to start with the largest aquarium you can reasonably afford and maintain (the taller, the better). In general, a tank of at least 40 gallons (150 L) is preferable since that’s the size when one begins to see significant benefits in terms of the greater stability a larger volume of water can provide. An aquarium of 40-gallons or more will be more resistant to overcrowding and to rapid fluctuations in temperature, pH, and salinity than smaller setups. The larger the aquarium the larger the margin for error it offers the aquarist and the greater the benefits it provides in terms of stability. Since seahorses orient to the substrate, a rectangular footprint is appreciated since it provides more bottom space and horizontal swimming room.

It is equally desirable to select an aquarium at least 20-inches high when keeping the greater seahorses. They need the vertical swimming space to perform their complex mating ritual and successfully complete the egg transfer, which is accomplished while the pair is rising through the water column or drifting slowly downwards from the apex of their rise. If the aquarium is too shallow, eggs will be spilled during the transfer from the female to the male’s brood pouch, and mating becomes increasingly difficult or impossible below a certain minimum depth. A tall aquarium can also help protect the seahorses from depth-related health problems such as bloated pouch and certain forms of Gas Bubble Disease

You’ll want to have external filter that can provide mechanical, chemical and biological filtration on your seahorse setup. A wet/dry trickle filter is excellent and many hobbyists also have good results with the biowheel filters. Or a good canister filter with the spray bar return would be another good choice.

You’ll want some well cured, "debugged" live rock to provide stability and denitrification ability, plenty of hitching posts for the seahorses, and a substrate of live sand (I prefer Nature’s Ocean reef sand, especially their black sand). I find that Instant Ocean artificial salt mix is more than adequate for seahorses. In general, seahorses do best with moderate water currents and relatively low light levels.

When it 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 excessively 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. Some species are even believed to be nocturnal (e.g., Hippocampus comes and H. ingens) and have no trouble seeing and feeding at night. Seahorses will do just fine under ambient room light with no aquarium light fixture whatsoever, although hobbyists prefer to keep their tanks illuminated for aesthetic purposes and so they can view them better.

So either an ordinary incandescent bulb or standard fluorescent tube is great. Between the two, I would strongly favor a fluorescent light fixture because they give off less heat (overheating and heat stress can become problems for seahorses during summertime heat waves) and because the fluorescents are more economical to operate. Easier on the old electric bill.

Paul Groves, curator at Underwater World in Perth, recommends combining a triphosphor (6500k) fluorescent tube with a Phillips TL Blue fluorescent tube to produce the best overall lighting for a seahorse exhibit. After much experimentation, he found the above combination of lights really encouraged the coloration of the seahorses as well as being aesthetically pleasing to the eye. He reports that the diversity in colors displayed by Hippocampus subelongatus was much less under any other lighting.

But 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 the 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.

As always, try to maintain stable water conditions within the following aquarium parameters:

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 = 0-10 ppm

That’s a quick rundown on the basic aquarium requirements for large seahorses such as Mustangs and Sunbursts (Hippocampus erectus), Josh. If you contact me off list ([email protected]), I would be happy to send you a lot of more detailed information explaining how to create an ideal environment for seahorses in your aquarium. And don’t forget that you can search this forum for more specific information as well.

Best wishes with all your fishes, Josh! As an experienced marine aquarist, I’m sure you would do well with hardy, highly domesticated Ocean Rider seahorses, sir.

Happy Trails!
Pete Giwojna