Seahorses are fascinating creatures that you can enjoy in your own home with proper knowledge of their husbandry. My mom had her own aquarium business when I was growing up and for 8 years we had a seahorse-centric tank in the living room, hosting both common and dwarf species at different times.
The following is a beginner's guide to care for a seahorse focused aquarium. Using a combination of mom's tried-and-true methods and information from both the web and the manuals we started our first tank with, I hope to arm you with all you need to know should you decide whether a seahorse aquarium is something you can commit to. They're really wonderful and entertaining pets, and captive bred specimens are more available than ever!
*My apologies in advance for using more web photos than I usually do. Since I am not currently keeping seahorses this was the only way to illustrate some of our core points. No copyright infringement intended--this is educational! Where possible, I photographed my own supplies and techniques, and highlighted important information.
Step 1: A Buyer's Guide to Seahorses
The "common seahorse" (scientific name Hippocampus Kuda) is the type you'll most often see for sale in aquarium shops. This species is considered "tropical" and is a bit easier to care for than those requiring colder waters. They come in many colors, ranging from light sandy brown, to yellow, to black. Since I couldn't find any local vendors currently stocking seahorses, I've demonstrated the color range using my dry specimens. You'll see how we go all the way from blonde/yellow to black. *For anyone concerned, these horses all died of natural causes after happy lives in our home tank. I dried and saved them. I do not support the industry that captures, kills, and dries seahorses for medicines or decorations. Not cool, dudes!
Many seahorses will shift colors depending on their environment, so don't be surprised if your seahorse appears different in your home tank than in the store, or even fluctuates within different parts of the home tank.
Seahorses offered for sale should be at least 3 inches long. Anything younger than that is likely too delicate for the home hobbyist.
Some mail order companies/breeders will offer the larger species and exotic colors, but these are best reserved for experienced seahorse hobbyists only. All marine creatures you see in a pet shop will have been shipped at least once, which can be stressful for the animal. I personally avoid ordering live animals by mail. Shipping a live animal in the mail is very stressful for the animal and may precipitate health problems due to temperature drops/rises or going too long without food. Also, I prefer to hand select stock to be sure I'm getting something that is healthy to begin with. If you do choose to order via mail, ask the breeder about their shipping practices. Find out how many days the package will be in transit, and request the use of hot or cold packs, depending on the current weather conditions. A reputable vendor will be doing this as common practice, for the health of the seahorse.
A Healthy Seahorse Will:
Have active eye movements. Eyes should also be clear, not cloudy.
Hitch to objects in the tank and generally be positioned upright.
Eat Regularly and appear well fed (no sunken in belly or sides).
DO NOT Buy a Seahorse That:
Has cloudy or inactive eyes --these are signs or disease.
Has very irregular or labored breathing --watch the gills and mouth. If the seahorse seems to be gasping for breath, this isn't a good sign.
Has skin that is sloughing off or any lesions--also signs of disease or parasites.
Has extreme bloating of the belly--this is a sign of internal gas bubble disease. If the seahorse seems ballooned up, it is likely already too late to treat the issue.
Lays down on their side for extended periods or can not seem to hold themselves upright when hitched to something. A number of ailments may ultimately result in this behavior. A seahorse displaying these issues may not survive long in your home tank.
For a comprehensive illustrated guide of seahorse diseases and treatments, visit this helpful site.
Do not be afraid to ask the breeder or shop keeper questions! They should be able to provide you with all the answers needed to make an informed purchase. If they can't or the answers seem fishy (pun intended?) do not buy from that vendor or wait to speak with someone more in the know.
Questions to Ask:
How long have you had your current batch of seahorses? If they just came in yesterday, you may want to wait a few days before buying. Waiting will allow you to confirm who is in good health and who is eating well.
Are they eating well? Confirm that the seahorse(s) you're interested have actually been SEEN eating food. It is not adequate to dump food in and walk away, just assuming everyone is filling up. Sometimes a seahorse will watch the food, but never strike. Since seahorses can eat multiple times a day, your breeder/shop keeper might offer to feed while you watch, so you can observe for yourself.
What are they currently feeding on? It is important to know whether the seahorses are being fed live food or frozen so that you can provide them with the same. If you'd like to try converting your live feeding horses to frozen, this will need to be done gradually over time by offering both. You will need to watch and confirm that they will eat the frozen food before relying on that diet completely.
For even more in-depth info on buying healthy horses, visit fused jaw.com. While doing web research to brush up, I found them to be among the most detailed sources of advice.
Step 2: Captive Bred or Wild Caught?
If the label on the shop tank does not specifically say, another good question to ask is whether the seahorses are captive bred.
If the option is available, ALWAYS go for captive bred over wild caught! Captive breeding has been going on successfully for over 15 years, so there's no reason to support the sometimes cruel industry of wild capture.
Wild caught seahorse are exactly that --taken from the wild ocean. Many will not survive the trip to be in a shop tank, and those that do will likely have short lives. As with many other animals, wild caught seahorses do not adjust to captivity well. They will often refuse to eat and definitely will not be interested in frozen (dead) foods. They can also harbor parasites, which might exist in tolerable levels while in the ocean but then get out of control when the stress of travel shifts the balance of their health.
A "Captive Bred" seahorse had parents who lived in a tank, was born in a tank, and has lived its entire life in ...you guessed it...a tank. They have never, at any time, known the ocean. The term "captive" may sound negative, but in this case it is a big plus. Captive Bred seahorses make for much happier and healthier pets. It is unlikely that they will have parasites and they will be most likely to accept a variety of live and frozen foods. They may even, on occasion, be more sociable with their owners. Rather than viewing you as a predator to hide from, they understand that the big blob outside the glass is the bringer of food. We had one female, Winnie, who would actually come up and hitch to your finger if you put it in the water. She also lived the longest of all our seahorses.
*I'm not proposing anyone try to train their seahorses to do this, and honestly sticking your hand in the tank a lot is not a good idea. What can I say? We were kids and holy crap was that magical to see!
You may also see some seahorses advertised as "Tank Raised". My understanding is that this may mean the parents were taken from the wild and gave birth shortly after, or the seahorse was very young when it was captured. As long as it has grown large enough for sale, you're probably in the clear. Just be sure to ask about what foods it readily accepts.
Step 3: Tank Specs
Tank size: The minimum height should be no less than 18 inches. Our seahorse tank (pictured here) was an acrylic 15 gallon, hexagonal vertically formatted tank which worked very well. We were always told that seahorses prefer vertical format tanks, but as long as there is room to roam, they certainly appreciate horizontal space too. Both directions are important for courtship behaviors.
Be sure that your filtration system does not create an overly strong current in the tank. Seahorses are very light and do not have a lot of fin power. Strong currents will send them zinging around like leaves on a blustery day! You want to create a moderate/calm tank environment; Flow rate minimum of 10x/hr to a max of 20x/hr. Basically, you need enough of a current to prevent debris from just settling and gunning up your water. Take care to cover/ protect your filter input and overflow points so that seahorses can not get sucked into them!
Gallon size recommendations online seem to vary. Some places say 10 gallons per pair of seahorses is adequate, others say a minimum of 20 gallons per pair. An expert from FusedJaw.com suggests no less than 30 gallons for a pair of large species seahorse. We had 3-4 at a time in the 15 gallon with no troubles (this was over a decade ago, so standards may have changed as our knowledge of sea life has expanded). The last time I kept horses a few years ago, I only did a single pair (smaller species) so they'd have more room. I'd say if you have the space for a larger tank, opt toward the upper end of size recommendations.
Water temperature should be around 74 degrees F. Some forums suggest a range of 73-77, but our visiting expert also urged users to go for the lower end at 74 to reduce the risk of bacterial infections.This may seem a little cold, especially for something "tropical" but this is important to maintain. High temperatures encourage bacteria growth and may contribute to health issues due to overproduction of said bacteria. An easy way to keep track of your water temp is to get one of those temp reader strips that sticks to the outside.
PH should be 8.1-8.3 Test periodically or whenever you do a water change to ensure this is being maintained. I found that LA water required the use of powdered PH adjuster to become acceptable.
If you don't have one already, you'll need a Hydrometer to monitor Specific Gravity. For those new to salt water aquariums, Specific Gravity means salinity. Some fish like saltier water than others. Seahorses thrive in an SG of 1.021-1.024. This can be measured very simply with a device as shown in the photos. Scoop a sample of your tank water into the device and watch where the needle registers. Most Hydrometers will indicate the "Good Zone", as seen with the color code here. The water I tested in the photo is tap water, which as you can see, registers NO salinity.
Remember that water will continually evaporate from your tank while the salt is left behind. This will mean you'll occasionally need to add fresh, de-chlorinated water to maintain your desired SG balance.
For more specifics about Nitrates, Ammonia, and other testable water conditions, see this helpful chart.
Step 4: Tank Furnishings
As with any salt water aquarium, a bed of crushed coral or ocean sand is most advisable. These foundations will support helpful micro-life within your tank. A layer of 2-3 inches is adequate. Do NOT use regular aquarium gravel like you would for freshwater, no matter how colorful and pretty it may seem.
The best piece of furniture you can provide for seahorses is a Sea Fan. It provides a network of different hitching possibilities at multiple levels, and will also look great in your vertical format tank. Hermit crabs love these too!
Stick with the vertical trend! Just like in western movies, every horse needs a good hitching post. Long grassy plants and corals/ faux corals with finger like extensions provide great cover and perching opportunities for seahorses. If you buy real coral, find out if it was responsibly harvested. There are some very nice, natural looking faux options available on the market if you're not sure how to find out.
Live rock makes a nice addition to any salt water set up. Most retailers of salt water fish will have a tank just for supporting live rock and will have already "cured" it before marking it for sale. Ask to be sure. Live rock pieces bring a multitude of great little organisms to your tank's ecosystem; good bacteria, plant life, worms, and more. Micro organisms can help keep your tank cleaner and provide food sources for each other --circle of life!
If you are buying dry live rock, it will reconstitute and grow the "life" back over time in your tank. Look for pieces with lots of nooks and crannies. Porous rocks make a better home for your micro-friends than smooth rocks.
Step 5: Feeding
Hopefully you've been able to procure a captive bred seahorse who readily accepts frozen foods. It just makes life a lot simpler.
Feed 2-3 times daily. Once a day is NOT enough, as it is with some fish. Monitor how much your seahorses are actually eating per feeding. You don't want a ton of excess on the floor because that'll just muck up your tank over time.
Watch this video clip to see feeding in action! Seahorses creep up slowly and then snap up the food.
Your main staples for a seahorse should be Brine Shrimp and Mysis Shrimp. Of these, brine shrimp is arguably the most popular, but make sure you acclimate your seahorses to eating Mysis, either frozen or live. It is a more nutrient dense food and will help maintain healthy weights better than the diet of Brine alone.A diet of brine exclusively will eventually cause wasting, due to inadequate protein/fat content.
Frozen foods are usually sold in blister packs that resemble ice cube trays. Each portion can be popped out to thaw in a small plastic medicine cup. Thaw using the warm, salty water from your aquarium. NEVER mix your frozen food with tap water to thaw! Tap water just contains too many mystery components and it isn't worth contaminating your tank.
Live Brine shrimp is probably the most readily available feeder for marine tanks. If you buy in a large quantity there will be hundreds of shrimp per bag. You may need to set up a small holding tank or bucket (never used for anything but this purpose) just for them.To keep them full of nutrients for your seahorses, you will need to provide them with nutrients. Squirt bottles of liquid "Brine Shrimp Food" (Phytoplankton) are your best bet.
You can also buy small set ups (about a cubic foot, if memory serves) to hatch your own brine shrimp at home. This gives you a variety of sizes to choose from and might(?) be a money saver, but let me tell you that tank stunk to high heaven! My mom, an experienced aquarist and not easily grossed out, sold it and never looked back!
Live Copepods-- Copepods are tiny organisms great for fish will very small mouths, like seahorses. These would be a very important part of the food pyramid if you had Dwarf Seahorses, which are maybe 1.5 inches tall. Stores that sell marine supplies and fish foods will sell them in squirt bottles, which provide directions on how to maintain them. One popular type is "Tigger Pods" I assume named such as they are bright orange and the way they move is sort of bouncy. I never used these for seahorses, but I can report that they worked well for my very old and finicky Mandarin Goby.
Feeder Guppies --a Caution: Newborn guppies are also a readily available feeder fish sometimes offered to seahorses. Personally, I do not recommend these. Guppies in the "feeder" tank can vary in size. If a guppy is one day too old to really be considered a "newborn" it is going to be too big to fit down your seahorse's snout. Put simply, they're a choking hazard. We lost 2 seahorses to this (proven by holding their dried bodies up to the light and seeing a guppy stuck in there) and quit offering them. It is very hard to tell just looking at the fish in the bag whether they're truly small enough, so use at your own risk.
Step 6: Breeding
It is advised to keep seahorses in pairs or groups, never alone. They enjoy company and can get sad if kept solitary. Unlike many wild animals, you can even house two males together and they will get along fine.
Knowing the body shape differences between males and females will help you understand what/who you're buying. The arch of a male's body is more of a "D" shape, whereas a female has a lower belly and could be said to be "P" shaped. You may also see a pouch on the male if breeding as occurred. While my dried specimens here were different ages, you can see the gender differences.
Seahorses will only breed under absolutely optimal conditions. I had always been told not to expect it to happen, but as our ability to meet seahorse needs has advanced, apparently more and more people write into forums asking how to STOP their little breeding machines! I suppose the simplest solution, if you don't want a ton of babies, is to have same gender roommates rather than a male-female pair. Consider that baby seahorses are more intensive to care for, least of which due to their incredibly tiny mouths and incredibly tiny food needs. Leave breeding to the experts!
If you are at an expert aquarist level, this may be a venture you're up for. Since this is a basics tutorial and I have no experience breeding seahorses myself, I will let you research that independently. If you choose to embark on this journey, please breed responsibly. Ask yourself these questions:
Would I keep all the babies?
Do I have the space and resources to care for them?
If I am going to sell/ re-home them, how do I screen interested parties to ensure my animals go to responsible new owners?
Do I know a reputable aquarium shop who would take/ buy the babies? Do I feel ok with the fact shops do NOT usually screen their buyers for experience level?
Step 7: Suitable Tankmates
Many keepers will advise that you keep your tank seahorse exclusive. There's good logic behind that, since they're feeding habits are rather unique.
If you do wish to give your seahorses a tank mate or two (tank size allowing) there are a few very congenial candidates to choose from. We kept all of these in our home tank at some point so I can attest to their compatibility. Apologies for the slightly blurry pics. The subjects at my local marine store were not interested in posing.
Peppermint Shrimp --Non-aggressive and will not disturb the seahorses. A Peppermint Shrimp (named for the red/white stripes) makes a great janitor. He can feed on the frozen shrimp scraps your seahorses failed to snap up.
Mandarin Gobys -- both spotted and red varieties are BEAUTIFUL and lots of fun to watch! Males have a little spike on their dorsal fin. Most importantly, they are slow moving floor dwellers with tiny mouths just like your seahorse.Their eating habits are similar and you don't have to worry about the fish stealing food before the seahorses can get to it. Gobys are sometimes shy and may pick favorite hiding spots within tank. These are some of my absolute favorites and ours lived a long time.
Firefish-- Another very pretty, but often shy, small fish. Docile and not an aggressive competitor for food, so your seahorses will get what they need.
DO NOT pair seahorses with aggressive, quick, or territorial fish!Almost all Damsels are a prime example of this. They will dart out and zap up all the food before your seahorse even has a chance to focus, and they may also bully other fish despite their small size.Damsels are very entertaining, but should be kept in a much different type of community tank. My childhood favorite was a blue Damsel named Sharky, who lived to be over 10yrs old! He got so big we had to give him to one of my mom's clients, an optometrist with a very large marine tank.
Step 8: Full Speed Ahead!
I hope this guide has left you feeling well informed about seahorse care. Seahorses have been one of my favorite exotic pets, both wondrous and easy to manage once you understand their needs, and I enjoyed sharing them with you!
If you liked this Ible, please swim over and vote for me in the Pets Challenge!
*To any salt water aquarium enthusiasts out there: Please chime in with your experiences! My account is based on the "easier" tropical species I've kept, and what has been available to me locally. Thus, we didn't discuss chillers and a lot of the other extras that are needed for large or cold water species. If you have something you'd like to share with other readers that isn't covered in these basics, please contribute in the comments.