So You Want To Set Up A Seahorse Aquarium

By: | Date: 01/02/2011 | No Comments |


A beautiful seahorse aquarium with seahorse artwork. Photo courtesy of Stephanie Loveland.

Laurie Smith gives us a brief overview of what is needed to get started with seahorses.

So you want to set up seahorse aquarium. Welcome to the obsession.

The Aquarium

The fist thing I recommend is to buy the largest tank you can afford, but no smaller than a 29 high, unless you are planning on keeping dwarf seahorses, but I am talking about the larger species here and will get to dwarf keeping at another time.

Seahorses like tall tanks. A good rule of thumb for tank height is 3 times the full-grown length of the seahorse species you want to keep. Most of the larger seahorses are between 6-8 inches in length so you would want a tank that is 20-24 inches deep at a minimum.

Example 29 Gallon Aquarium

Filtration and Flow

Once you choose your tank you need to decide on filtration. Seahorses are hard on the bioload of a tank so over filtering is a great way to go. Get a big sump or refugium for the tank. You can use canister filter, but be sure to get one that is rated for a tank that is larger than what you have and be sure to do regular monthly maintenance. I would also recommend weekly 10% water changes when using a canister filter. A protein skimmer is another piece of equipment you’ll want to have in your sump or as a hang on the back type if you are using a canister filter.

The flow rate in a seahorse tank should be on the lower side, but not too low. A turnover rate around 10-15 times per hour is good. You should also provide areas of lower flow when setting up the aquascaping in the tank for resting spots. Be sure to cover anything in the tank that a seahorse could get their tail stuck in and/or injured on. Powerhead intakes and heaters can seriously hurt a seahorse. The best place for a heater is in the sump.

Contents: Sand. Rock and Clean up Crew

Live sand and Live Rock work well in seahorse setups. They will help keep the tank cleaner and make for a nice natural setting for the tank. Be sure to do a hyper salinity (very high salinity) dip on the live rock before adding to the tank to help rid it of any unwanted pests.

After the tank has cycled adding various types of macro algae will also be good. The macros will provide hitches for the seahorses as well as places for pods to hang out for the seahorses to eat. Many types of macros will also help remove nitrates from the water.

Adding a clean up crew will round out your tank. Snails like nerites, nassarius, and ceriths are great scavengers and will help keep the tank clean. I also keep scarlet hermit crabs in my tank to help eat any leftover food and algae that grows on the rocks. Peppermint Shrimp are also great CUC members.

54 gallon bowfront aquarium with seahorses.

54 gallon tank with gorgonian and sponges built by husband and wife team. Photo courtesy of Maroonman.


Another thing you will want to get is a chiller. ‘But I am getting tropical seahorses you say’. You will still want a chiller. It is best to keep a seahorse tank around 72-74*. This helps to keep the bacteria levels down so the horses will stay healthier.

Temperature and Seahorses


Seahorses don’t need special lighting. What you are putting in with them may require special lighting though. If you go with higher output lights be sure to have areas where the seahorses can get out of the light. 8-10 hours of light is a good photoperiod amount.


Before you order your seahorses be sure to set up a quarantine tank for them to go into when you first get them. This way you can observe them and make sure that they are OK and eating before placing them in to the display tank. A bare bottom 10-gallon tank with hitches works well for this. You will need to do daily water changes and siphon out the poo to help keep the ammonia levels down. An ammonia level alert tag in the tank is a good idea too. Three to four weeks should be long enough in quarantine.

Where To Find Quality Seahorses

When purchasing seahorses be sure to get seahorses that are captive bred. There is some confusion on the difference between captive bred, tank raised, and wild caught. Captive bred means that the seahorse was born and raised in a tank. Tank raised is usually a wild caught seahorse that was caught as a juvenile and raised to adulthood in a tank. They are basically the same as wild caught. Purchasing captive bred seahorses will benefit not only the ocean’s population of seahorses, but your wallet as well since your seahorse will be healthier.

I highly recommend purchasing seahorses from Seahorse Source. They are excellent breeders and offer great customer service. Your seahorses will arrive happy to see you and healthy. There are also members on here that sell good quality seahorses. Where to buy seahorses.

Seahorses can be kept singly, or in pairs and groups. Most seahorses will be happier if kept in pairs or groups though. If you don’t want to raise fry same sex tanks are fine to set up. Most people go with females when doing this so they don’t need to worry about pouch trouble.

Tank Mates

Seahorses typically do best in a species only tank but there are a few fish that will work as tank mates. You’ll want to choose fish that aren’t aggressive or won’t out compete the seahorse for food. You will also want to be sure that any corals you put in the tank with them won’t sting them and can also hold up to being hitched on. Check out’s excellent Tank Mates Guide.


Seahorses have very short digestive tracks and need to be fed at least twice a day. Feed a high quality food like PE Mysis or Hikari Mysis. Gut loaded live ghost shrimp, or adult brine shrimp make a tasty treat for seahorses and will help get them some extra nutrition. Use products like flake food, NatuRose or spiralina for gut loading and feed them once or twice a week. Watching seahorses eat live food can be quite entertaining.

More information on feeding seahorses.

Life Span

When properly cared for seahorses can live for 5 or more years. I know of some that have lived over 8 years.


Seahorses are great pets to have as long as you can provide a proper environment and care for them. They are very personable and will really get under your skin. They become a part of your family much like a dog or cat will. It will become an obsession.

Editors note: I’ve added in some additional links that can help you get started.

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Two Seahorses, Hippocampus breviceps, photographed during a dive
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"Unlike most other fish, they [seahorses] are monogamous and mate for life." - National Geographic It's a theme repeated over...