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WOW! This is a waaaaaay out of date referance. Please do not refer to this information for tank sizes, medication or tankmates. It is based on what we knew back in 2003 which was 7 years ago - we have learned a lot since then!!!

I will try to get the updated version live and correctly installed quickly. In the interrum, please refer to the linked PDF file. It is also a few years old, but offers better information, the current 'state of play' will be up shortly! PDF PRINTOUT

“Seahorses are strange, beautiful, oddities of nature. But the very things that make them so
fascinating to humans now threatens to lead them to extinction.”

- ABC News

UPDATED: 26 December 2003

As many aquarium hobbyists know, seahorses and related species have different needs than other marine fish. This fact sheet was created to assist anyone that is interested in keeping these fascinating fish. The content herein is meant to be a guideline for new seahorse keepers based upon the experience of several hundred seahorse hobbyists, Syngnathidae researchers, and commercial breeders.

IMPORTANT NOTE: Although we discuss wild caught (WC) as well as captive bred (CB) seahorse strongly advise buying CB seahorses. Captive breeding prevents decimation of wild populations and supports responsible and innovative breeding programs for those interested in becoming seahorse breeders. In addition, captive bred seahorses are much easier to keep, having been trained to accept frozen food, pre-adapted to aquarium conditions, and much less likely to carry or spread disease. Their survivability in captivity is significantly higher than that of wild caught seahorses. In the end, it is more cost effective and rewarding for the beginning hobbyist to purchase CB seahorses.



If you are buying from a local fish store (LFS), observe the seahorses carefully before you purchase. If you are buying from an e-tailer, be sure they have a reputation for supplying quality animals and a guarantee of live arrival and survival for 5-7 days. Even the smallest sign of disease or injury can result in a mortality, as seahorses are extremely sensitive and often succumb to pathogens not common to other marine ornamental fish. To make matters worse, treatments are quite different and have fewer efficacies. The following are some questions to ask of your local fish store or e-tailer, particularly if you are purchasing WC animals. If you are able to observe the seahorses onsite, the following guidelines can help you with picking out the best animals that are most likely to survive. Even with a careful eye, WC seahorses can look outwardly healthy, only to die within a few days of purchase. Though there are no guarantees when purchasing WC seahorses, this may help to minimize mortalities:

Photographer: Karen Barber
Is the seahorse eating? What food is it eating and how often is it being fed? Is the body well - rounded with no signs of abdominal concavity?

DO NOT BUY A SEAHORSE THAT IS NOT EATING. Even stressed, new arrivals should eat within 24 hours if it they are otherwise healthy and kept in a clean, well-aerated tank. Often they have only been offered brine shrimp, which is not a normal food source in their native habitats. Although this is not a healthy diet, if the seahorse will take it readily, it is the first sign of good overall health. However, if the seahorses have been in the pet store for any length of time, fed exclusively on un-enriched brine shrimp, there is a good chance these specimens will be malnourished. Seahorses only have a rudimentary stomach and must continuously absorb nutrients. Offering a non-nutritional diet for more than several days will quickly deplete the seahorse of necessary nutrients, making it more susceptible to pathogens. Most malnourished seahorses do not survive in the long term.

It is a better sign if the pet store is feeding a more adequate diet. This could include enriched brine shrimp, ghost shrimp (for larger seahorses), Hawaiian red shrimp, or frozen mysis or similar crustaceans . You are much more likely to succeed with a seahorse that is trained to eat frozen food, and it is cheaper and easier to obtain and provide frozen food. Most CB seahorses have been trained to eat frozen mysis or similar appropriate food. Of the WC seahorses, H. erectus, the lined seahorse from the North American Atlantic seaboard, has the reputation of being easiest to train to eat frozen foods. As part of a complete diet, seahorses trained to eat frozen food should regularly receive a variety of live foods as well. Examples include ghost shrimp, enriched brine shrimp, baby mollies, red shrimp, etc. Some live food should be offered every week. (Note: The dwarf seahorse, H. zosterae, is a hardy species, but requires live food cultures of brine shrimp nauplii (24+ hour post-hatched vitamin/HUFA enriched baby brine shrimp), but is very hardy if its nutritional needs are met.)


Are there any signs of skin sloughing or discoloration, inflammation, odd swimming behaviour, not using a holdfast, lying on substrate or hitching upside down, minimal eye movement, protruding eyes, blisters anywhere on the body, inflamed gill slits, eroded snout, any body or tail lesions, or continuous heavy respiration?
This is only a partial list of possible outward signs of illness. It's also difficult to know what is normal behaviour (e.g., normal eye movement, respiration) without an experienced eye for seahorse observation. If any of the above descriptions are present, play it safe and pass on the purchase. Resist buying an apparently healthy animal if its tank mates show signs of disease, as it is likely to be infected as well. To "rescue" an obviously malnourished or sick seahorse is tempting. Try to resist the temptation; most sick seahorses will die, and you risk introducing disease pathogens into your

aquariums. In addition, you will be rewarding an aquarium shop for poor husbandry practices and for selling unhealthy WC seahorses. Instead, urge the store to maintain and feed seahorses properly and to stock CB animals.

CB seahorses, maintained in a mature tank with good water quality (ammonia and nitrite, zero; nitrate <20 ppm) and fed an appropriate diet may be expected to live for several years without serious health problems. WC seahorses, on the other hand, often show signs of

Photographer: Tamara Weiss
disease, particularly as they are being newly established in the home aquarium. For either WC or CB, it is imperative to have medications on hand, so that you can be prepared to treat a disease outbreak before it overtakes one or all of your animals. The following medications have been recommended by the author and members of to keep on hand in case of illness. Before treating, be sure to diagnose the disease and determine the best course of treatment. The "Articles" section in the library includes information on diseases and treatments, and the discussion board has an Emergency forum staffed by experienced keepers and breeders to help with your questions.


You should have these medications on hand when you purchase your seahorse. As you become more knowledgeable about them, you may find that you prefer other medications; this is just a guideline. Most of these medications can be found at a well-stocked LFS.
Be sure to have on hand:
Formalin 3 and Neosporin (triple antibiotic ointment) as a topical solution.
(Betadine will do in a pinch.)
Methylene blue
Furan-2 or Triple Sulfa

Maracyn II
Paragon II
Malachite Green
Important meds that may be obtained through your veterinarian or MD:
Acetazolamide (Diamox)
Ceftazime (Fortran)
Praziquantel (Droncit)

Essential tools to have on hand:
Fine gauge IV catheter flexible tubing (without needle)
Tuberculin syringe with needle removed
Loose hairpin with soft plastic tip

NOTE: is attempting to make the essential medications and tools available through the website.


Acclimation procedures do not differ from other fish except for the use of nets, as netting often damages the bony plates and the delicate dermal layer of the seahorse. Preferable methods include gently coaxing them into a plastic container for transfer or hand transfer. If the latter method is used, it is advisable to make the transfer quickly to avoid undue stress.

All WC purchases should be given a freshwater dip or formalin bath and ideally be kept in a separate display or quarantine tank for 2-4 weeks before introducing them to a tank with other seahorses. Seahorses are more sensitive than most fish to the FW dip, thus if they show signs of distress (e.g. thrashing, lying on bottom) lasting more than around 15 seconds, remove them immediately, regardless of the maximum 3 -5 minutes required to remove or kill external parasites. We do not advocate mixing CB and WC seahorses in a tank, as even apparently healthy WC seahorses may be asymptomatic carriers of disease that could decimate CB seahorses that may not have resistance to the disease. Observe all new purchases carefully for any odd behaviour or external lesions, spots or other anomalies. Usually the first sign of illness is cessation of appetite, but this is not a hard and fast rule. If any signs of illness are suspected, there is a comprehensive disease guide at

Alternately, you can post the problem on the discussion board under Emergency if anything seems amiss. There are several expert keepers who will be around to help you with the problem and answer your questions. Please do not treat a seahorse without knowing what pathogen is affecting it. Additionally, never use copper-based solutions on seahorses or pipefish. Their internal organs are too delicate to withstand copper treatments.


Seahorses should be introduced into a mature, cycled aquarium. Numerous filtration methods and tank set-ups can result in a healthy, stable seahorse aquarium. A seahorse tank must have gentle to moderate currents. Be sure there is adequate biological filtration and do regular, partial water changes of 5-20 percent per week as you would with any fish-only aquarium, to keep water parameters as listed below. Water parameters should be stable before animals are added:

pH - 8.0 to 8.3
Specific gravity - 1.021 to 1.024
Ammonia - 0
Nitrite - 0
Nitrate - <20 ppm

Optimum temperature is dependent on whether the seahorse species being kept are tropical, subtropical or temperate. Generally, most beginners should start with tropical species unless the tank is equipped with a chiller unit. Heating tanks is much less expensive than cooling them. Use a high quality submersible heater. Many members use Ebo Jaeger heaters as they have more reliable than average performance and do not feel hot to the touch, minimizing the chance of burning a seahorse that hitches to the heater. Allow about 4-watts per gallon when selecting an aquarium heater.

This is not a hard and fast rule, but most seahorse aquarists use taller tanks. Seahorses need height (2.5 to 3 times the UNCURLED length of the animals) in their tanks to court and mate. At a minimum, the depth of the tank, excluding the substrate, should be at least 2x the uncurled length of the animal. Further, leave a path along the substrate as some seahorses courting rituals require them to scoot along the bottom of the tank in tandem. Several pairs of pygmy seahorses can be maintained in a 5-10 gallon tank (a 10G is recommended because of the difficulties of keeping water parameters stable in a small capacity aquarium. Two to three pairs of medium sized seahorses can be maintained in a 24-gallon tank although a larger tank is preferable to keep water parameters more stable.

Temperature Requirements and Stocking Density of Commonly Available Seahorse Species
Note: This is to be used as a guideline. Keeping temperature constant is extremely important and although it is typically better to keep them at the lower ranges below, stability is key. One degree more or less is not a problem as long as temperature swings do not exceed 2 degrees maximum in a 24-hour range. Surface turbulence using power heads (water pumps), air pumps, and fans can help to lower and stabilize temperatures if necessary.

Photographer: Eliezer Zuñiga Villarreal

Here is a list of commonly avaliable seahorse species grouped by their temperature range. You can not mix species from differing temperature ranges. Also listed is the recommended minimum tank size for two pairs of adult seahorses of each species, as well as the 'additional' space required by each additional pair. These are guidelines. Several people keep seahorses successfully in much smaller tanks, but we do not recommend this.

1) Tropical species - kept at 74-78 degrees F (24-26 degrees C)
zosterae, 1 pair/1.5 gallons (6 liters) - recommended 5 gallons (20 liters)
kuda, 1 pair/8 gallons (30 liters)- minimum size 15 gallons (60 liters)
barbouri, 1 pair/8 gallons (30 liters)- minimum size 15 gallons (60 liters)
erectus, 1 pair/8 gallons (30 liters)- minimum size 15 gallons (60 liters)
reidi 1 pair/8 gallons (30 liters)- minimum size 15 gallons (60 liters)
fuscus 1 pair per 5 gallons (20 liters)- minimum size 10 gallons (40 liters)
comes 1 pair/8 gallons (30 liters)- minimum size 15 gallons (60 liters)
procerus 1 pair/8 gallons (30 liters) - minimum size 15 gallons (60 liters)

2) Subtropical species - kept at 70-74 degrees F (22-25 degrees C)
whitei, 1 pair/8 gallons (30 liters)- minimum size 15 gallons (60 liters)
ingens1 pair/13 gallons (50 liters)- minimum size 45 gallons (180 liters)
tuberculatus, 1 pair/5 gallons (20 liters)- minimum size 15 gallons (60 liters)

3) Temperate species - kept at 66-72 degrees F (19-22 degrees C)
abdominalis, 1pair/13 gallons (50 liters)- minimum size 60 gallons (240 liters)
capensis 1 pair/5 gallons (20 liters)- minimum size 10 gallons (40 liters)
breviceps, 1 pair/5 gallons (20 liters)- minimum size 10 gallons (40 liters)



The following hardy invertebrates are generally regarded as safe tank mates for medium to large seahorses and do not require special lighting, as do corals. Use caution when adding animals to the tank; seahorses are not strong swimmers, are not competitive feeders, and have very few defenses against aggression. With the exception of these clean-up crew animals it is generally advisable to
establish seahorses first, then add other animals. Remove a tank mate at the first sign of aggression. Many potential tank mates can help control algae and/or clean up uneaten food. Other animals such as certain non-aggressive fish and corals may be housed with seahorses; this is just a partial list of compatible "clean up crew" animals considered most likely to be safe with small to large seahorses. Not all of these animals should be considered safe with seahorse fry. See the tank mates section of for a more comprehensive list.
Photographer: Robert Sozzani

NOTE: Be sure you research the requirements of any compatible animals you wish to add to the seahorse tank before purchasing. For example, many corals, sponges, and gorgonians require special reef lighting or high water flow to thrive.

Fan worms including Feather Dusters (Phylum Annelida)
Astrea Snail (Lithopoma [Astraea] spp.)
Turbo Snail (Turbo spp.)
Nassarius Snail (Nassarius vibex)
Trochus Snail (Trochus niloticus)
Cerith Snail (Family Cerithiidae)
Nerite Snail (Nerita spp.)
Fighting Conch (Strombus alatus)
Blue-legged Hermit Crab (Clibanarius tricolor)
Skunk Cleaner Shrimp (Lysmata amboinensis)
Peppermint Shrimp (Lysmata wurdemanni)
Scarlet/Blood Shrimp (Lysmata debelius)
Rockpool Shrimp (Palaemon elegans)
Grass Shrimp (Palaemonetes vulgaris)
(Shrimp are not considered safe around seahorse fry or H.zosterae (dwarf seahorse).

Notable groups that should be avoided:
Tangs, Triggerfish, Groupers, , Eels, Nudibranchs, Filter-feeding Sea Cucumbers, Sea Urchins with sharp spines, Fireworms, Spanish Dancer Flatworms, Fire Corals, Lace Corals, Anemones, Tube Anemones, all Cephalopods (Squids, Octopuses, Cuttlefish, and Nautilus-), Mantis Shrimp, Lobsters, Heliofungia spp. Corals, Cataphyllia spp. Corals, Euphyllia spp. Corals, Goniopora/Alveopora spp. Corals, Galaxea spp. Corals, and Hydnophora spp. Corals.


With a little patience, WC seahorses can be trained to eat dead/frozen foods. There are numerous ways to coax them into taking it. (You can find a "how-to" at under "Articles" which explains the procedure.) This not only makes the job of feeding them a great deal easier and less expensive, it increases their chances of long-term survival, particularly with less experienced seahorse keepers. If you are having a lot of trouble getting your new seahorses to take frozen food, a short-term solution is to feed enriched artemia, (brine shrimp), ghost shrimp for larger species; and Hawaiian red shrimp. (See for enrichment procedures.) The need to start with live food is usually necessary when purchasing WC seahorses unless the staff at your LFS has already trained them. It is good husbandry to continue to regularly offer live foods to seahorses that primarily subsist on frozen foods. Try to offer live foods at least once or twice a week.

The enriched artemia should always be rinsed in freshwater prior to feedings to kill or remove any harmful bacteria, and offered two to three times per day at three to six hour intervals. Some larger seahorse species may not readily take the brine shrimp, and will require live ghost/glass shrimp. These are a much more nutritional food source (or supplement) than the artemia-only diet. Finally, if you don't want to go to all this trouble maintaining the WC seahorses, your other option is to purchase only CB (captive bred) species that have already been trained to eat frozen foods, such as mysis (Mysis relicta), or mysids making feeding a much more simple task. Offer the frozen food, pre-thawed and rinsed, once or twice daily. Initially watch the seahorses carefully to see that all are getting their fill, and then adjust the amount of food offered accordingly. Again, remember to supplement a diet of frozen food with live foods offered at least once per week.


Often, temperate species are available for the home aquaria. One of the most popular species currently being sold is the pot-bellied seahorse, H.abdominalis or H.bleekeri. This is a wonderfully active, curious seahorse that has captured the heart of many hobbyists. If you choose to carry them, it is critical to hold them at optimum temp ranges (66-70F/19-21C). You will need to purchase a chiller to maintain optimum temperatures. Be forewarned that chillers are very expensive pieces of equipment.

NOTE: Any fact sheets purporting that these species can be kept at tropical temperature ranges is false and will, without exception, cause the demise of a subtropical and temperate species within a few days. It is in your own best interest not to purchase from breeding facilities that claim otherwise, nor to disseminate this misinformation.


Most of the WC seahorses supplied to pet stores are collected from the tropical Indo-Pacific or Caribbean regions. These species are most comfortably kept at temperature ranges between 74-78F/24.5-26C. There are several species regularly offered, but again, many of these same species are also being domestically bred. You can find excellent photos and descriptions, and other specifics on each species at Many new seahorse hobbyists purchase seahorses from their local aquarium dealer without being aware of which species they own. We frequently get questions on species ID and care at If your dealer is not certain of the scientific name of the species of seahorse he/she
Photographer: Barry Lipman
carries, you can ID your species at Photo Gallery at . If still unsure, a digital photo may be uploaded and linked to on the site. One clear photo showing the dorsal spines and head/snout should be sufficient for ID purposes. Common names can be misleading. Find their scientific equivalent and make sure you find out about any specific needs particular to the species purchased.

BEFORE YOU BUY, be sure you understand the basic principles of how to keep seahorses in the home aquarium. Again, the best overall source for this is at Keeping marine fish of any type requires a solid knowledge of basic marine chemistry. There are many books available and sources on the internet on this topic. If you prepare adequately and take the time to set up an appropriate sized, fully cycled, and stable tank environment for your seahorses, you will greatly improve your chances of success.

NOTE: Although temperature ranges may be similar, it is not wise to keep tropical seahorses in a captive reef environment. They cannot compete for

Photographer: John Randall
food and may be stressed by pelagic fishes, such as tangs and wrasses. The water circulation in a standard reef tank is much higher than the low to moderate water turnover for seahorses. In an attempt to find a holdfast, they may grasp onto corals and anemones, consequently receiving a potentially deadly sting. Seahorses are best kept in a species tank; that is, a tank specifically set up for keeping primarily one species.
Check with your LFS or at for information on how to best obtain a particular species.
No matter where you live, it is not usually difficult to have CB seahorses ordered for you from your LFS.
This fact sheet was created for the new seahorse hobbyists by (, a nonprofit organization committed to the education and ethical treatment of seahorses in captivity. Please distribute this document freely to all parties interested in keeping seahorses.
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