By Bob Goemans
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Horses in My Aquariums

Authored by: Bob Goemans

First printed in TFH, November 2006

Like most long-term aquarists, every once and awhile I get a desire to maintain a fish species that requires quite different environmental conditions than most of the other ‘ordinary’ species generally kept in my aquariums. This usually meant establishing a totally separate aquarium environment that suited a specific type of fish. And when this desire about 20 years ago concerned seahorses, it was oblivious they would require not only an environment dedicated to their needs, but that I additionally needed to do some research as to their diet and general health needs since I didn’t have any previous experience with them.

In those days, it was off to the local library to research projects! As for seahorses, I became aware they are in the Order Gasterosteiformes and are placed in the Suborder Syngnathoidei, where they are in the Family Syngnathidae, which consists of both seahorses and pipefishes. And their genus name ‘Hippocampus’ is Greek for ‘hippo,’ which means horse, and ‘kampos,’ a sea monster. In ancient times, there were many myths about these strange looking creatures, even the thought it was a marine insect, not a fish!

Today, that the entire Family contains about 52 genera having about 200 species, with seahorses in the subfamily Hippocampine (one genus with about 30 species) and pipefish, the remaining, in the subfamily Syngnathinae.

Research showed that seahorses mostly inhabit shallow marine environments, such as seagrass beds and mangrove areas, where gentle currents exist. That their scales are modified into close fitting plates that form a flexible armor and that seahorses swim in an upright fashion with their ‘horse-like’ head angled downward, whereas pipefish, a more snake-shaped fish, swim in an eel or snake-like fashion. Furthermore, both have small tubular mouths for feeding on tiny crustaceans and drifting plankton-like animals. I also learned that seahorses have a prehensile tail for holding onto various kinds of substrate and mainly use their dorsal and pectoral fins for locomotion. And they range in size from an inch (2.5 cm) to more than a foot (30 cm) and can somewhat change color to match their surroundings. Also, that the male gives birth because during courtship the female places her eggs inside the male’s pouch where they become fertilized. When its time for their birth, the male goes into epileptic-like movements expelling tiny replicas of mom and dad. Another interesting fact learned was that most have a short life span, i.e., two to three years, with dwarf seahorses having only a years life span.

The more I read, the more interested I became and the next step (of course) was actually setting up a small aquarium to house these interesting creatures. An old 10-gallon all glass aquarium and its undergravel filter that was languishing in my garage became an ideal size tank to house a few seahorses. It took over a month before I considered the tank ready for the first seahorse inhabitant. The reason for this was its nitrification cycle was being accomplished with the help of a few blue damselfish. Keep in mind this was about twenty years ago. These would not stay in the aquarium because they would make ‘nasty’ tankmates for seahorses, as anything bolder and/or a faster swimmer would be unacceptable where seahorses are concerned. Once the cycle was complete, the damsels were removed and they went into an existing 125-gallon fish-only tank that I had at that time.

A week later I searched several local shops and found none had any seahorses. But they did have some different forms of Caulerpa and placed some of that into the tank. I also placed some artificial wood branch-like ornaments in the aquarium so its future inhabitants could have secure mooring places. The only water movement in the tank was from the UGF exiting water flow from its upward flow air bubble tube in the corner of the aquarium. But that sufficed as seahorses are poor swimmers. Once the seahorses, two males and one female, were in the aquarium, it received a sectioned glass cover, and a small heater and low wattage incandescent light. If memory serves me correctly, I used some egg-crate material to surround the heater so the seahorses would not be injured if they touched it when hot.

The biggest difficulty I had with this system was with feeding the seahorses. I was not retired in those days and my time home was quite limited. I would often stop on the way home from work at different shops to pick up some live brine shrimp. This made the commute home much longer (I drove 50 miles each way to work), something my significant other was not pleased with. (There were no cell phones in those days and was simply ‘sometimes’ late for dinner!) Occasionally a friend would give me some baby guppies or mollies, which really perked the interest of the tanks three inhabitants! I would also occasionally try some flake foods, but most of the time that did not fare too well. I actually spent ‘far’ more money on fish food than what my three seahorses originally cost! But they were worth it, as I often enjoyed watching them feed and slowly poking around the aquarium. And don’t ask what species they were, as I still don’t have any idea, as they were simply sold as “Seahorse’s” in those days. In fact, they were quite drab, and not as colorful as some are these days. Yet color often depends upon mating periods, surroundings, and nutrition.

And because I fed quite frequently ‘when possible,’ their tank probably became very nutrient rich, as the Caulerpa grew very well. Occasionally, some of it was traded for live brine shrimp. All in all the tank went well, and only once saw some fry, which were probably eaten by the adults because it never went any further. About eight months later, I decided to construct a very large complex reef tank, and the remaining two seahorses and tank were given to a local shop, which set it up on their countertop, where it made a very nice display for their customers.

Today, the same thoughts hold true when it comes to the size aquarium and environment they should be maintained in. A small aquarium makes it easier for them to capture their food, thereby conserving some of their energy. Gentle currents are also important, as they are poor swimmers, and of course, be careful where you place heaters. And since air can get trapped in their bodies the use of airstones should be limited or at least carefully applied. And they should not be kept in aquaria containing anemones or any aggressive or faster swimming tankmates. In fact, some small pipefish make good tankmates.

Fortunately, there are far greater levels of formation today, as there are species choices, and with the WorldWideWeb at our fingertips, those who want to maintain these fascinating creatures can do so quite easily. Additionally, there’s a greater abundance of foodstuffs available today, making their feeding easier and more nutritious. And keep in mind, they not only require the proper habitat, they require two to three feedings per day. In fact, a full-grown specimen can eat over 60 adult brine shrimp per day! One of the better foodstuffs is the frozen freshwater mysis shrimp, Mysis relicta, which contains an abundant source of HUFA's (Highly Unsaturated Fatty Acids). Both adult live brine shrimp and thawed mysis shrimp should be additionally fortified with products such as American Marine Selcon or similar products.

When shopping for seahorses, look for individuals that are alert, body coverings are clear of any white spots or damage, and are swimming in a normal fashion. And if there are others in the same tank, be sure they also are in good shape, because if one has a problem, no doubt the others have an existing problem, but possibly not yet showing it. If everything looks good, then ask the shop owner to feed that tank and make sure your selection will eat. I would also suggest that the individual of choice be dipped out with a container instead of netted out. Netting out seahorses causes undue stress and possible body and fin damage, often leading to secondary infections. In fact, I always insist on that when purchasing large fish such as angelfish and tangs. And don’t be surprised if a somewhat colorful seahorse specimen becomes somewhat drab in your tank. This is quite normal and depending upon species can be somewhat alleviated by feeding enriched foodstuffs.

Since there is a lot more information available these days, I recommend reading up on what species is of interest before diving in so to speak. And when that time comes, it would be much better if you chose a captive-bred specimen. This would at least guarantee the animal has not been starved and/or subjected to poor water quality holding areas and long distance shipping stresses; as such animals can be a source for developing maladies. In fact, while recently walking the many local wholesaler and transshipper areas in and around the Los Angeles airport, I saw a tank with what I was told were recently arrived wild caught seahorses that looked less than healthy. Even though these wholesalers do everything possible to recondition those individuals, those animals have undergone extreme levels of stress in getting from their area of capture to the present location. Therefore the chances of a disease being in an early stage of development are often very good. For that reason and the fact the supply of Mother Nature’s wild caught specimens are dwindling, my first choice would be captive-bred individuals.

And I should add, as for Mother Nature’s dwindling supply of seahorses, the far majority of that problem is due to ‘dried’ seahorses being used as medicine in many countries. In fact, it has been estimated that about ‘15 million’ specimens are annually dried and ‘consumed’ for this purpose! Add to this the destruction of their natural habitats for home development/business opportunities, and it’s another good reason to only utilize captive bred specimens if the keeping of seahorses is something you want to try! Lets not, as concerned aquarists, add to the declining amount of specimens in the wild!

Even though my experience with these interesting creatures is very limited, it seems most sold in the trade is H. erectus, H. kuda, and H. hystrix. Nevertheless, there are a wide variety of hybrids available that is already accustomed to closed systems and frozen foods such as mysis shrimp. For much more specific information on these interesting creatures than what I can provide, I highly recommend contacting Carol at

References/Good sources of information:

Giwojna, Pete. 1990. A Step-By-Step Book About Seahorses. TFH Publications, Inc., Neptune City, NJ.

Goemans, Bob (2005) Aquarium Library.

Hargreaves, V.B. 2002. The Complete Book of the Marine Aquarium. Salamander Books Ltd., London.

Louri, Sara A., Vincent, Amanda C.J., and Hall, Heather J. 1999. Seahorses: An Identification Guide To The World’s Species And their Conservation. McGill University, Quebec, Canada.

Masonjones, Heather D. and Lewis, Sara M. 1996. Courtship behavior in the Dwarf Seahorse, Hippocampus zosterae. Copeia (3): pp 634-640.

Michael, Scott. 1998. Reef Fishes’ Volume 1, Microcosm, Shelburne, VT.

Straughan, Robert P.L. 1961. Keeping Seahorses. All Pet Books, Inc.

Strawn, Kirk. 1954. Keeping and Breeding the Dwarf Seahorse. Aquarium Journal, V25, #10: pp 215-218, 227, 228.

Vincent, Amanda C.J. 1990. Reproductive Ecology of Seahorses. Ph.D. Thesis, University of Cambridge: pp 42-64.

Vincent, Amanda C.J. & Sadler, Laila M. 1995. Faithful pair bonds in wild seahorses, Hippocampus whitei. Animals Behavior 1995, 50,3: pp 1-13.

Vincent, Amanda, Ph.D. 1995. Keeping Seahorses. Journal of Maquaculture (Winter 1995) V3, #1: pp1, 5, 6.

Kingdom: Animalia

Phylum: Chordata

Class: Actinopterygii

Order: Gasterosteiformes

Suborder: Syngnathoidei

Family Syngnathidae (Seahorses & Pipefishes)

Genus Hippocampus (Seahorses)

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