tank set up

Dear AD:

Okay, it sounds like you have a pretty good idea about the types of things you need to add to your 20-gallon hex tank in order to make it suitable for seahorses.

Yes, a protein skimmer is an optional piece of equipment for a seahorse keeper. A good protein skimmer is beneficial in many ways but it is certainly not a prerequisite for keeping seahorses successfully. Just be sure that you provide good surface agitation and aeration for your hex tank in order to assure good oxygenation and to promote efficient gas exchange at the air/water interface. One of the benefits of protein skimmer provides is that it helps to keep the dissolved oxygen levels in the aquarium high, so if you decide to do without a protein skimmer, you’ll want to provide another form of surface agitation and aeration to help oxygenate the tank. That’s especially important for a tall tank with a small footprint and limited surface area, like your hex tank.

A canister filter with a spray bar return positioned just above the surface of the water would be a good way to accomplish that, and would also provide good water circulation without being too overpowering for the seahorses.

In general, you want the filter for your seahorse tank to be able to turn over the entire volume of the aquarium at least five times every hour. So, for your 20-gallon hex tank, you will want to look for a canister filter that is rated for at least 100 gallons per hour. I would look for a canister filter that you can equip with a spray bar return, because having a spray bar return positioned so that it roils the surface of the water not only provides excellent surface agitation and oxygenation, but also greatly attenuates the water currents produced by the filter. With a spray bar return, you could have a canister filter that turns over the entire volume of your 20-gallon hex tank 10 times every hour or more without generating too much turbulence for the seahorses in a tall tank like yours. So, if you select a canister filter that you can equip with a spray bar return, you could get a more powerful unit that is rated for 200 gallons per hour with no problems, AD.

Get yourself a good canister filter (a hang-on design is fine) that can provide efficient biological filtration as well as mechanical and chemical filtration, and that can be equipped with a spray bar return, and you really can’t go far wrong for the type of tank you have.

As for the seahorses, the highly domesticated Mustangs (Hippocampus erectus) are a great choice for a beginner. They have been captive bred and raised for more generations than any other seahorse species, so they are supremely well adapted for aquarium life. They are very hardy and are aggressive eaters that have been trained to accept frozen Mysis as their staple, everyday diet from a very early age. But they are large, robust seahorses, and as a beginner, I would recommend that you keep no more than a single pair of Mustangs in your 20-gallon hex tank.

If you want to keep more seahorses than that in your 20-gallon hex, then I would recommend that you start out with a smaller species such as the Black Seapony (Hippocampus fuscus) instead. The H. fuscus are also very hardy aquarium fishes that eat frozen foods very well and are relatively easy to breed and raise. But they are medium-size seahorses — more like the Shetland ponies of the seahorse world — and more than one pair of the fuscus would be comfortable in a 20-gallon hex tank.

Ocean Rider does not raise H. fuscus, but captive-bred-and-raised specimens are sometimes available from Oceans, Reefs, & Aquariums in Florida. They are listed as Hippocampus breviceps on ORA’s website, but that’s due to a misidentification, and they are actually genuine H. fuscus, as they will explain if you contact them.

If you contact me off list ([email protected]), AD, I will provide you with lots more information about both the H. erectus and H. fuscus to help you determine which species might be best suited for your needs and interests. And I will e-mail you with some detailed instructions for setting up your aquarium to create ideal conditions for either the H. erectus or H. fuscus, whichever you feel is best for you.

Have you had saltwater aquariums before, AD, or is this your first venture into the marine aquarium hobby? If you are new to saltwater aquarium keeping, as well as to seahorses, there are a couple of good books that would be very helpful in getting you started off on the right foot with this hobby.

There are two books that I highly recommend for all inexperienced marine aquarists. An excellent place to start would be to read the book "The New Marine Aquarium" by Michael Paletta. Next I would suggest you follow that up by perusing "The Conscientious Marine Aquarist: A Commonsense Handbook for Successful Saltwater Hobbyists" by Bob Fenner. Those are both outstanding books for a beginner that will give you an good grasp of the basic things you need to know to maintain a marine aquarium.

After you’ve had a chance to digest The New Marine Aquarium and The Conscientious Marine Aquarist, and have a better understanding of the basic principles involved in keeping a saltwater aquarium, you should next study a good guide book devoted for seahorses. I would say the most useful of these for your needs is "How to Care for your Seahorses in the Marine Aquarium — A Stable Environment For your Seahorse Stable" by Tracy Warland. All of the books I have mentioned should be available from your local library or can be purchased from any of the major booksellers.

Best wishes with all your fishes, AD!

Happy Trails!
Pete Giwojna