This article originally appeared in SeaScopeTM, Volume 12, Winter 1995, Aquarium Systems, copyright 1995. All rights reserved by Aquarium Systems, Mentor, Ohio. Permission to reproduce is granted by the publisher to The Breeder's Registry and is not transferrable.
by Thierry Schmidt
Mulhuse, France
Yellow seahorse (Hippocampus kuda) from the Indo-Pacific. (Photo by Scott W. Michael) |
Which aquarist hasn't been attracted by the strange beauty of a seahorse drifting from one coral to another? That's the reason why a few years ago I bought my first specimen of Hippocampus kuda. Keep in mind that it is a fish and not an invertebrate, and that it can reach a length of about 25 centimeters (cm), or 10 inches. This species is the most common seahorse in the Indo-Pacific ocean, where it swims slowly among seaweed and algae. Color varies with locality, from black to brown, white, yellow, and even red individuals.
Keeping these fantastic animals doesn't present any special difficulties as long as you keep in mind some general guidelines. They must be in an aquarium with minimal water movement and many places to attach to such as coral branches, gorgonians, or Caulerpa.
They are well-suited for a reef tank containing less active fish and
shrimp such as Stenopus sp. or Lysmata grabbami. The
aquarium should not contain any big sea anemones. Seahorses could
think them potential food and be trapped by them.
Seahorses are not very active fish, and don't need a large aquarium. I keep a group of ten in a 240 liter (65 gallon) aquarium. This is the minimum size I would recommend to maintain adequate biological balance. My aquarium is lighted by four 30 watt Triton fluorescent tubes for 13 hours a day. Caulerpa taxifolia grows well with this length of day. The tank bottom is covered by a 5 cm layer of coral sand. The background is composed of Reeforms® synthetic coral, especially Acropora palmate and Turbinaria sp., along with big pieces of lava. I believe that aquarists should buy only synthetic coral in order to preserve the natural reefs.
Lined seahorse (H. erectus) male giving birth. (Photo by Scott W. Michael) |
When considering aeration, keep in mind that newly hatched seahorses, as well as some older ones, will eat small air bubbles, mistaking them for food, and then die. Use only airstones that produce big bubbles, or, better yet, put the airstones out of reach of the seahorses. Circulation in my tank is supplied by an internal filter with a flow of 3 to 4 times the tank volume an hour. There is also a canister filter with a flow rate of 440 liters (110 gallons) per hour that is connected to a 15 watt UV sterilizer that runs 5 hours a day (not the normal 24 hours). Although a UV sterilizer is an expensive investment, I think it is a profitable one, because I have not had to add medication in many years. I also have a Visi-jet PS100 protein skimmer on this tank that is very efficient at removing colors and wastes from the water.
I maintain good water quality by making regular water exchanges. This prevents a drop in pH and a slow increase in nitrate. I change 10% each week by mixing Instant Ocean® with fresh tap water to a salinity of 1.022 to 1.023 at 24C (74F). I have used Instant Ocean® successfully for 10 years to keep and breed seahorses.
Seahorses should be fed two to three times a day. A major obstacle for many hobbyists is the need to feed seahorses with live foods such as adult brine shrimp, mysid shrimp, or young fish fry. Contrary to popular opinion, it is possible to get seahorses to accept frozen food, especially Mysis or krill. It will take time to acclimate them to take these foods. Try using newly hatched guppies or other similar fry, and gradually move to freshly dead food. This may not be possible if there are other fish in the aquarium.
If seahorses are maintained in good health they will reproduce regularly. The male is easily identified by his incubation pouch. He holds the female by the tail and in a graceful ballet invites the female to deposit eggs in the pouch. The eggs hatch 20 days later. This is the only example of a male incubating eggs.
It is a beautiful sight to see a batch of newly hatched seahorses, 10 to 100, depending on the size of the male's pouch, drifting in the aquarium, each a miniature of the adults. Feeding is difficult because of the small size of the fry. The best chance for success is isolating the babies. I scoop them out with a plastic cup early in the morning or evening, depending on the time of hatch. The young are phototropic (attracted to light) and easily drawn with a small light to the surface for collection. Do not use a net or expose them to the air. I transfer them to a 10 liter (2.5 gallon) aquarium containing an air driven filter, a heater, and with a natural daylight exposure. I change 25% of the water each day. I hold the pH at 8, the nitrate at 10 to 15 milligrams per liter (mg/1), the salinity at 1.022, and the temperature at 24C (74). During the first few days I feed the juveniles rotifers, Brachionussp., and Artemia nauplii. Later I continue with Artemia and then newly hatched fry, such as guppies. In spite of a high death rate I am able to raise at least a part of the spawn. There is usually a month between each spawn.
Seahorses seldom live more than three years, so it is very important that aquarists breed them. It is possible. I encourage all marine aquarists interested in keeping these beautiful little fish to try it.
Editor's Note:
The most common problem encountered in raising juvenile seahorses is nutrition. Recently, enrichment formulas such as Selcon® have been made available to hobbyists. Developed for marine aquaculture, these supplements improve the quality of the rotifers and brine shrimp by supplying essential marine fatty acids and vitamins.
Because of pressure. from the curio trade and health food markets, seahorses are being over-fished in some areas. Thus, efforts to breed these interesting animals are essential.
