Seahorse Care Guide

By: | Date: 10/17/2003 | 3 Comments |
Lined seahorse in aquarium

Lined seahorse in a home aquarium.

Editors note: This article was updated November 29, 2012 to reflect changes and advances in seahorse keeping.

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.

IMPORTANT NOTE: Although we discuss wild caught, tank raised, and captive bred seahorses, we strongly advise only buying captive bred 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 captive bred seahorses.


Tank raised seahorses are similar to captive bred seahorses, and the two are often confused, sometimes intentionally. Tank raised generally means a fish that was raised in captivity for a time. In seahorses, usually means the parents were born in the wild, and the male is captured and placed in captivity while pregnant to give birth, and the offspring are then raised. It can also mean juveniles caught in the wild and then raised up in captivity.

While this is better in some ways to wild caught, it presents it’s own problems. They are often raised in unfiltered seawater, and therefore have the same parasites that wild caught seahorses do. While they are usually trained to eat frozen, there is no guarantee. They also often carry many of the same pathogens wild caught seahorses do. They are often sent too small, and most tank raised seahorses come from overseas, so the trip is too much for such young seahorses. They have had a record of poor survival in captivity. It’s strongly advised to avoid tank raised seahorses. If you are purchasing from a local fish store, it is wise to ask if they are tank raised or captive bred, but be aware they may not know the difference. You should also ask the source, and if they’re not sure, avoid those seahorses.

Purchasing Healthy Seahorses

The first place to look for healthy captive bred seahorses is through a breeder. There are several online that ship, and you might be able to find a local breeder by contacting reef and aquarium clubs in your area. If you are buying from a local fish store (LFS), observe the seahorses carefully before you purchase. If you are buying online, be sure the company has 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.

Captive bred Hippicampus ingens

Captive bred pacific seahorses available from a breeder in Mexico. Photo by Eliezer Zuñiga

The following are some questions to ask of your local fish store or online store. 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, wild caught and tank raised 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:

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 frozen mysis, enriched brine shrimp, ghost shrimp (for larger seahorses), Hawaiian red shrimp, 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 captive bred and tank raised seahorses have been trained to eat frozen mysis. As part of a complete diet, seahorses trained to eat frozen mysis should regularly receive a variety of foods as well.  (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.)

Signs To Observe For Potential Problems

Are there any signs of skin sloughing or discoloration, inflammation, odd swimming behavior, not using a holdfast, lying on substrate or swimming 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 behavior (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 seahorses. Instead, urge the store to maintain and feed seahorses properly and to stock captive bred animals.

Captive bred 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. Tank raised and wild caught seahorses, on the other hand, often show signs of disease, particularly as they are being newly established in the home aquarium.

It is wise to have medications on hand or know what stores stock good medications, so that you can be prepared to treat a disease outbreak before it overtakes one or all of your animals. This is especially true for wild caught and tank raised seahorses. The following medications have been recommended to keep on hand in case of illness. Before treating, be sure to diagnose the disease and determine the best course of treatment.

Is the seahorse over 3″?

Many Tank Raised seahorses are often sent to the US too small and therefore have a poor track record for survival. Some are as small as 1 ½ inches. These seahorses are still considered fry (baby seahorses) by most breeders, and are still very fragile at this stage. Many fish stores don’t tell you how big they will grow and so these small seahorses are placed in aquariums that will be too small in the long term. Also being so fragile at those small sizes, they can easily be stressed and die with no apparent cause. (An exception to this rule is H. zosterae, which rarely grows over 1 inch.)

Recommendations For The Medicine Cabinet

It is a good idea to have these medications on hand when you purchase your seahorse or familiarize yourself with local fish stores to know which ones carry these medications. 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.

Recommended Medications:

  • Formalin 37%
  • Bio-Bandage powder
  • Furan 2
  • Triple Sulfa
  • Methylene blue
  • Kanamycin
  • Neomycin
  • Fenbendazole (Pancur)
  • Metronidazole

If your local fish store does not carry these medications, it is advised you purchase them online in advance of any problems to ensure you are prepare if any problems should arise. The few days it takes to order medications may be too long for a fast acting disease.

The following medications are also useful in severe cases but are only available through a veterinarian or MD:

  • Acetazolamide (Diamox)
  • Ceftazime (Fortran)
  • Praziquantel (Droncit)
  • Doxycycline (Vibramycin)

It is strongly advised you build a relationship with an exotic vet in case of illness. Few vets are experienced with seahorses, but if you find one that works with reptiles, amphibians, or even other types of fish, they’re usually willing to help as long as you understand their limitations.

Essential tools to have on hand:

  • Fine gauge IV catheter flexible tubing (without needle)
  • Syringe without needle

Acclimation and Quarantine

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 wild caught and tank raised seahorses should be given a freshwater dip and ideally be kept in a separate display or quarantine tank for a minimum of 4 weeks before introducing them to a tank with other seahorses. A freshwater dip should have matching temperature and ph to the aquarium water and should be performed for 8-10 minutes. Observe the seahorse very closely during this time. If it thrashed around and twitches, this is a likely sign that it has parasites, and the freshwater dip is effective. Only remove a seahorse if it stops breathing for an extended time.

It is advisable to quarantine all seahorses, including captive bred ones, to watch for any signs of disease as well as get them acclimated to eating in an environment where it is easier to control foods. A small cycled 10 gallon aquarium with some plastic plants for hitching is usually adequate. True captive bred seahorses only need a 2 week quarantine period unless they are showing signs of disease. The aquarium must be fully cycled first. Having a 10 gallon aquarium and supplies on hand is a good idea in case of sickness or the surprise birth of baby seahorses.

Do not mix captive bred, wild caught, or tank raised seahorses in the same tank, as even apparently healthy tank raised and wild caught seahorses may be asymptomatic carriers of disease that could decimate captive bred seahorses. Observe all new purchases carefully for any odd behavior 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.

The Seahorse Aquarium

Seahorses should be introduced into a mature, cycled aquarium. Most commonly used marine filtration methods and tank set-ups can result in a healthy, stable seahorse aquarium. A seahorse tank should have moderate currents, and intakes should be covered. One common misconception is that they require very little flow. In recent years, its been discovered they do best with a reasonable flow. A turnover rate of 10-20 times the aquarium volume per hour is a good rate. Be sure there is adequate biological filtration and do regular, partial water changes of 5-25 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 8.4
  • Specific gravity – 1.021 to 1.026
  • Ammonia – 0
  • Nitrite – 0
  • Nitrate – <20 ppm

Optimum temperature is dependent on whether the seahorse species being kept are tropical, subtropical or temperate. Seahorses do better at cooler temperatures than one would use for other tropical fish. 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, but ensure that the heater has a guard to prevent burns, as a seahorse may hitch to the heater. Allow about 4-watts per gallon when selecting an aquarium heater.

Brazilian Seahorse In Aquarium

Captive bred Brazilian seahorse (Hippocampus reidi) in an aquarium with artificial grass.

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 2 times the uncurled length of the animal. However, seahorses also use horizontal space as well, not only going about their daily activities, but as part of their courting ritual. Many first-time seahorse aquarists are surprised at how active their seahorses are. When placing decor and live rock it is a good idea to leave an open path along the substrate as some seahorses courting rituals require them to scoot along the bottom of the tank in tandem.

Temperature and Tank Size Requirements 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.

1) Tropical species should be kept at 70-74 degrees F (21-23 degrees C)

Species Minimum Tank Size Additional Per Pair
H. angustus 30 gallons (115 liters) 15 gallons (60 liters)
H. barbouri 30 gallons (115 liters) 15 gallons (60 liters)
H. comes 30 gallons (115 liters) 15 gallons (60 liters)
H. erectus* 30 gallons (115 liters) 15 gallons (60 liters)
H. fuscus 20 gallons (75 liters) 10 gallons (38 liters)
H. kelloggi 40 galllons (150 liters) 20 gallons (75 liters)
H. kuda 30 gallons (115 liters) 15 gallons (60 liters)
H. reidi 30 gallons (115 liters) 15 gallons (60 liters)
H. zosterae* 2.5 gallons (10 liters) 1 gallon (4 liters)

*H. zosterae and H. erectus come from both warmer and cooler waters and can generally tolerate water temperatures to what subtropical species can tolerate.

Editors note: Many aquarists starting out try and use 29 gallon Bio-Cubes and similarly sized all-in-one kit aquariums. Unfortunately they are not very good at keeping the temperature down to where seahorses need them. See the example 29 gallon aquarium for a basic aquarium setup that can support seahorses

2)  Subtropical species should be kept at  64-70 degrees F (18-21 degrees C)

Species Minimum Tank Size Additional Per Pair
H. capensis* 20 gallons (75 liters) 10 gallons (38 liters)
H. ingens* 40 gallons (150 liters) 20 gallons (75 liters)
H. subelongatus 40 gallons (150 liters) 20 gallons (75 liters)
H. tuberculatus 10 gallons (38 liters) 5 gallons (8 liters)

*Some people have kept H. ingens and H. capensis at tropical temperatures, there is some debate as to if they’re found at warmer temperatures in the wild. However, warmer temperatures can lead to bacterial disease, particularly tail rot.

3) Temperate species should be kept at 60-68 degrees F (16-20 degrees C)
Temperate species will most likely require a chiller to maintain the temperature.

Species Minimum Tank Size Additional Per Pair
H. abdominalis 65 gallons (250 liters) 30 gallons (115 liters)
H. breviceps 10 gallons (38 liters) 5 gallons (8 liters)
H. whitei 30 gallons (115 liters) 15 gallons (60 liters)

Potential Seahorse Tank Mates

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.

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.

  • Fanworms including Feather Dusters (Phylum Annelida)
  • Astraea 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).

*Cleaner shrimp of the order Lysmata won’t directly harm seahorses, but some hobbyists have noticed they can harass seahorses. Be sure to watch closely if you decide to add any of these shrimp. Peppermint shrimp seem to be the most docile of the group.

Notable groups that should be avoided:
Tangs, Triggerfish, Groupers, Sharks/Wobbegongs, Eeels, 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, Clams.


Captive bred seahorses are usually already been trained to eat frozen mysis, making feeding a much more simple task. Offer the frozen food, pre-thawed and rinsed, two to three times daily.

Younger seahorses need more frequent feeding, if it is small be sure to offer food at least 3 times per day. Initially watch the seahorses carefully to see that all are getting their fill, and then adjust the amount of food offered accordingly. You should supplement a diet of frozen food with live foods offered at least once per week. Some choices include enriched brine shrimp, live mysis shrimp, small ghost shrimp (If your seahorse is large enough), larval food shrimp, and Hawai’ian red shrimp.

If you have a seahorse that isn’t trained to eat frozen food, such as a wild caught seahorse, there are numerous ways to coax them into taking it. 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. The need to start with live food is usually necessary when purchasing wild caught seahorses unless they have already been trained by the staff at your local fish store. 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. Hawai’ian red shrimp can be purchased from various online sources in Hawaii. Mysis shrimp can be purchased from various companies in Florida.

Know Your Species

Often, temperate species are available for the home aquaria. This is especially true in Australia, where H. abdominalis, the pot-bellied seahorse, is commonly available in local shops. 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 (60-68F/16-20C). You will need to purchase a chiller to maintain optimum temperatures. Be forewarned that chillers are very expensive pieces of equipment.

4 seahorse species

Four seahorse species, from left to right – H. barbouri, H. reidi, H. whitei, H. erectus. They are tropical, tropical, temperate, subtropical.

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

Most of the seahorses supplied to pet stores are originally from the tropical Indo-Pacific or Caribbean regions. These species are most comfortably kept at temperature ranges between 70-74F (21-23C.) These numbers may seem a bit unusual for a tropical fish, but experience has shown that tropical seahorses do best at cooler temperatures because they are less prone to bacterial infections at those temperatures. Many new seahorse hobbyists purchase seahorses from their local aquarium dealer without being aware of which species they own. Do your best to get a scientific name from the fish store. Keep in mind, they still could be mislabeled. Better yet, only purchase from a breeder so you know exactly what you are getting.

BEFORE YOU BUY, be sure you understand the basic principles of how to keep seahorses in the home aquarium and be sure your tank is cycled and you have a cycled quarantine tank available. 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: It is ill advised to keep tropical seahorses in a captive reef environment. They cannot compete for 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 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 have also been known to damage the soft tissue of delicate sps corals frequently kept in reef tanks through constant hitching. Seahorses are best kept in a species tank; that is, a tank specifically set up for keeping primarily one species.

Resources For Captive Bred Seahorses

Most all common seahorse species, from temperate to tropical, are now being captive bred. The best option for obtaining healthy, captive bred seahorses is by going directly to a breeder. If you want a particular species, ask your LFS dealer to order captive-bred specimens for you. No matter where you live, it is not usually difficult to have captive bred seahorses ordered for you from your LFS. If unfamiliar with who to contact, you can recommend they get in touch with the following wholesalers who raise seahorses to find a distributor.

Seahorse Source
South Watch Seahorse Farms
ORA Farms  (Wholesale, your LFS can order)

Seahorse Australia

Simply Seahorses
Seahorse Breeder  

View more sources of captive bred seahorses.

If you are unable to obtain Captive Bred seahorses from a local store, many online shops that specialize in marine livestock are now carrying captive bred seahorses. seahorseOvernight shipping is safe and can help connect you to breeders that might otherwise be outside your immediate area.

No matter where you live, it is not usually difficult to have CB seahorses ordered for you from your local fish store or find a reputable breeder to purchase from.

3 Responses to “Seahorse Care Guide”

  1. ludwigvan_.beethoven Says:

    Thanks but you make keeping seahorses sound like you have to be a slave to them–no vacations, not to trust anyone to fill for you and barely able to go to work or school for fear they will die on you while u r away—if ucdate?????

  2. ludwigvan_.beethoven Says:

    Typo error—last sentence should read:’ if u do’

  3. TamiW Says:

    There is some truth to that. Vacations are very hard to coordinate for seahorse owners. It’s much similar to owning a dog or a cat, as opposed to a fish. Except boarding seahorses is rarely an option.

    Many people do not consider this when acquiring seahorses as pets, and then end up either stuck when it comes to travel, or attempting to leave their seahorses without proper care and returning to find the seahorses died in their absence. It is imparitive people know that this is a very challenging part of seahorse care.

    With the right planning, it can be done. But it’s not easy.

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