Dwarf Seahorses As Pets
Written By: Tami Weiss | Date Posted: February 23, 2009 | 38 Comments »
Newly Arrived Dwarf Seahorses
They arrived via postal mail one blustery January afternoon, circa 1988. One pair of dwarf seahorses, ordered from the back of a Field & Stream magazine. I placed them in a 10 gallon tank with an undergravel filter, my first marine aquarium. Little did I know this was a completely inappropriate set up for them. Yet these hardy, thumbnail–sized seahorses thrived.
Much has changed regarding our understanding of seahorse care, and many other species are now commonly available. Yet the dwarf seahorse remains an ever popular, easy to care for aquarium pet. The basics of keeping them are quite simple as long as you follow a few guidelines.
Biology
Before getting into their care, its important to understand a little bit about their biology.
Dwarf seahorses belong to the genus Hippocampus, which is the genus all seahorses belong to. Their species name, zosterae comes from the habitat they are usually found in. Zostrea is a type of seagrass, also know as eel grass. H. zosterae inhabit sea grass beds in the Gulf of Mexico, though its not limited to just eel grass. They prefer protected areas where the water flow is buffered from the main ocean currents, usually lagoons and sheltered areas near reefs. They occasionally are found floating in seaweed as well.
True to their name, the dwarf seahorse only grows up to an inch. Occasional oddball “large” dwarf seahorses are reported, but these are likely mis-identified juveniles of other species. Their main food in the wild is copepods, although other micro- and macro-scopic plankton is consumed. H. zosterae aren’t particularly long lived, having a life span between 12 and 18 month. However, they breed quite readily, and can produce three generations of seahorses per year in the wild. More in captivity where the seasons don’t influence breeding behavior.
Housing
Keeping dwarf seahorses have very basic housing requirements. They only need a small tank with a sponge filter to thrive. More complicated set-ups tend to be less successful. The reason for this is simple. Too much water flow created by mechanical filters stirs up the water too much for these weak swimmers. Stronger filtration also runs the risk of removing their food from the water column.
The size of the aquarium to house dwarf seahorses is the exact opposite of what you usually hear when keeping fish: You want to keep the aquarium appropriately small. The reason behind this is to maintain food density without compromising water quality. If you keep the seahorses in too large of an aquarium, you run the risk of them starving, or so much food being present that it doesn’t get eaten and fouls the water.
The specific size needed depends on the number of seahorses being kept. Below is a charge of how many dwarves for what size aquarium.
- 1 gallon: 2 – 3 to start, max 6 adults *Keeping an aquarium this small is a challenge to keep balanced, and shouldn’t be attempted by first time aquarium owners.
- 2.5 gallon: 4 – 6 to start, max 12 adults
- 5 gallon: 8 – 12 to start, max 20 adults
- 10 gallon: No fewer than 20 adults.
The tank should be set up and cycled before any seahorses are added. Cycling is the process of establishing the biological filtration that keeps the water clean. This is important especially since some vendors still suggest that dwarf seahorses can be added immediately to a new aquarium. While dwarves are frequently tough enough to withstand a cycle, ammonia burn and nitrite poisoning can cause long term complications. There is no point in risking the lives and health of this precious animal for a few weeks of cycling time.
A 5 gallon aquarium with artifical corals and plants
Generally you don’t want to use live rock for cycling the dwarf aquarium. Two methods that are commonly used are fishless cycling with ammonia and fishless cycling with shrimp. These techniques are beyond the scope of this article, but you can read about them here: fishless cycling with ammonia, fishless cycling with shrimp
Dwarf seahorse are subtropical, but can handle a wide range of temperatures as long as the change isn’t too quick. you can expect to successfully keep them between the temperatures of 65 and 80 degrees, with 68-74 being optimal. This means they don’t need a heater if kept in a normally heated house. A thermometer is a must though, to monitor for large temperature swings and the temperature going outside of the safe zone. Seahorses, while true marine fish, aren’t too picky about their salinity. Any specific gravity from 1.015 to 1.025 is acceptable as long as the change is made gradually. Take special care though, to replenish evaporated water every day. With a small tank, evaporation and replenishing water can cause wild swings in salinity.
Dwarves, just like the adults, need places to hitch. Many keepers opt for artifical decorations because of the risk of hydroids (see below.) Most basic aquarium plants work well. Macro Algaeas can be used but must be treated for hydroids. Live rock should be used with caution, as many pest can hitch hike in and harm the diminutive seahorse.
Food
Because of their size, dwarves need to be feed tiny live food. Fortunately, brine shrimp hatched from eggs fits this description, and is easy to hatch and raise. A small brine shrimp hatchery is easy to set up and maintain, and setup and feeding will only take roughly 15 minutes a day. The simplest set up is an inverted 2 liter soda bottle. You will need:
- Soda bottle
- Airline hose
- Air pump
- Valve
- Lamp
- Coffee filters
- Funnel
- Turkey baster
You’ll want to take the 2ltr bottle and cut about 1/3rd of the bottom off. Keep the bottom. Tighten the cap and turn the bottle upside-down. You should be able to take the bottom you cut off and rest the bottle inside of it. Fill that bottle half way full of saltwater at 35ppt (natural salinity level). Put an airline hose in the bottle to the bottom, and set the air to vigorously turn the water just a bit. You don’t want it so high that it could destroy the newly hatched brine shrimp. Now, place a lap pointed at the bottle – light is required to activate the enzyme in the brine shrimp egg that causes the egg to hatch. Add approximately 1/4 tsp of brine shrimp eggs.
After approximately 24 hours, the eggs will have hatched. Take the airline out, and let the brine shrimp sit for 15 minutes or so with the light off or in a darkened area. The brine shrimp will settle to the bottom, while the egg shells will float to the top. Once they’ve separated, take the turkey baster and suck out the brine shrimp from the bottom (they will be bright orange). Then line your funnel with a coffee filter, and filter the brine shrimp you took out with the baster in the funnel with the coffee filter. Once the hatch water has drained, give them a rinse with fresh water. You can now add the baby brine shrimp to the tank.
Dwarf seahorse fry surrounded by newly hatched brine shrimp
You’ll eventually figure out how much you want to add, but you’re looking to add enough so that the seahorses can eat pretty much constantly but not so much that there is a lot left over at the next feeding. You can put the unused baby brine shrimp in the fridge in fresh salt water for a second feeding later in the day. Ideally, dwarves should be fed twice a day. You can also set up a second hatchery, but refrigerating the unused baby brine shrimp is usually sufficient.
Dwarves need constant access to food, which means they have to be feed at least every day. They can not go prolonged periods without food, so if the aquarist is leaving town, they need to have someone pet sit who is prepared to hatch out live brine shrimp every day. They also do not work very well as office pets, as going a whole weekend without food could spell disaster for dwarf seahorses.
Breeding
Dwarf seahorse fry hitching on a piece of macro algae.
If you plan on keeping dwarf seahorses, sooner or later you will have babies. That’s just a fact of keeping the marine equivalent of guppies. Fortunately, the babies are extremely easy to raise. They can even be raised in the same aquarium with the same food as the parents.
Like other seahorses, it is the male that becomes pregnant. They are gregarious by nature, and don’t pair bond. In the wild, their breeding is limited by the seasons, but in the home aquarium they can breed constantly. The male can have a brood every 10 days, and can have 5-30 at a time. Most spawns are generally around 10 or so babies at a time. The babies hitch at birth, and will often be found hanging from the male’s head, snout, tail, etc… at birthing time.
One baby hangs on to the tail while another other emerges from the pouch.
Raising the young can be as simple as adding enough food to make sure that the babies are sufficiently fed. However, higher success rates are achieved by raising the babies separately. Its unclear why this might be; lack competition for food or possible unnoticed aquarium pests may be to blame. Raising the babies separately is quite simple though. All they need is a cycled aquarium set up like their parents. A bare bottom aquarium is even easier to keep clean for raising babies, and makes changing out the tank for each new brood much easier.
Whether you rear them in tank or on their own nursery, after about 6 weeks, they will start reaching sexual maturity and many will start acting amorous towards the opposite sex. Sexing starts to be possible, though some late bloomers may not show a pouch for a couple more weeks.
Acquiring Dwarf Seahorses
Dwarf seahorses are rarely sold in local fish stores so the beginning aquarist may wonder what to do about getting them. Even the occasional store that does get them in, they rarely have the knowledge or appropriate conditions to keep them alive. For that reason, its usually best to go through a mail order vendor.
Captive Bred
Seahorsesource.com
Wild Caught
Cramers Caribbean Critters
Many mail order vendors will send your seahorses via postal mail. However, while dwarves ship surprisingly well by these means, its in your best interest to have them shipped overnight. Incremental weather or delays in the mail system can kill the seahorses, and there is nothing more disappointing than opening a package filled with dead fish.
Hydroids!
Hydroid polyps on live rock.
No article on dwarf seahorses is complete without a discussion of hydroids. Hydroids are tiny stinging animals that resemble anemones and jellyfish depending on the stage in their lifecycle. They are present in most marine aquariums, but only become a problem when they are feed a constant supply of small, free floating foods. When that happens, the can spread in such large numbers that they literally cover every surface of the aquarium.
This poses a problem for dwarf seahorses for two reasons. In such large numbers, they can quickly consume all the food in the aquarium. However, a much bigger threat comes from their stings. Their sting isn’t particularly potent to most animals, but for the tiny dwarf seahorse, the sting can be deadly.
Eradicating hydroids is fortunately very simple. They are susceptible to the medication “fenbendazole”. It can be purchased at farm supply stores or online under the brand name “pancur”, which is a dewormer for horses, cats and dogs. Dosage is as follows:
1/8 teaspoon of the horse dewormer granules (22.2% fenbendazole) per 10 gallons of water. 25% water change 24 hours later.
*Be warned*, some inverts are also affected by this treatment. Worms, some snail, gorgonians and some corals can be killed by fenbendazole.
Many people opt for artificial decorations to avoid hydroids. You can remove the animals in questions and replace them after a partial water change and running carbon for 48 hours; however you run the risk of reintroducing hydroids back into the tank.
Just how do you know if you have hydroids? The first symptom is food disappearing faster than it used to. If you notice that, start looking in the tank for small jellyfish no bigger than 1/4 inch. This is the free swimming stage of hydroids. If you don’t find that, then look for brown or clear “fuzz” growing in the tank. It will be a dense mat, and on observing closely, you should see them stinging and consuming the brine shrimp you add to the tank. If you find you have hydroids, don’t panic, just follow the above guidelines for treating the tank.
Tankmates
Florida Pugnose Pipefish does well with dwarf seahorses.
Because of their small size, animals that are normally safe with seahorses can be a potential threat. Scavengers, such as hermit crabs and cleaner shrimp, can easily overcome and kill a dwarf seahorse. Even those tankmates that are okay with adult dwarves can easily consume baby dwarves. For that reason, people rarely keep other fish with their dwarves. I have experimented with a few different fish, and found that your cleaner gobies and firefish are the safest, though will sometimes eat babies. Some small pipefish do well with dwarf seahorses as well, though may have a tendancy to eat fry.
Snails are probably the best clean up crew. Nassarus snails can be used for cleaning up waste in the sandbed. Some people have said they’ve had success with small hermits but I would recommend against it. Some small shrimp, such as sexy shrimp and anemone shrimp can be kept, with caution, with dwarf seahorses. Most other clean up animals are inappropriate for dwarf seahorses.
I enjoyed reading your article and have added it to “Favorites”
March 9th, 2009 at 9:23 pmWhere can I purchase seahorses, I live in Boston, MA so Im assuming my best bet is via mail service but isnt that horrible to ship seahorses?
March 29th, 2009 at 11:17 amOrdering online is probably the best way to go. Shipping is fine for seahorses, as long as the shipper knows what they’re doing. In a lot of ways, shipping directly to the individual is better. That way they’re not sitting at a fish store where they may not have the specialized knowledge or set up for their care. A list of online sources is available here: http://www.fusedjaw.com/?p=127
For dwarf seahorses, I prefer Cramers Caribbean Critters.
March 29th, 2009 at 12:03 pmthe babies look so cute!!!!!! =0)
April 8th, 2009 at 10:17 amWill a watchman goby be a safe fish to keep in with dwarf seahorses? I read they are peaceful, bottom dwelling fish.
May 6th, 2009 at 7:15 amThank you,
David
That’s a tough call. The Tankmates Article says that they are a one – good with everything but might not be safe with seahorse fry. Dwarfs are a bit of an anomaly, being so small, but they’re larger than fry.
My guess would be that they’d be safe with adult dwarfs but might eat baby dwarfs. If you were to try it, I’d be sure to keep a close eye on the watchman goby for a few weeks, and have a net handing in case you have to remove it. If you really want to be safe, I’d suggest either a neon goby or firefish.
May 6th, 2009 at 4:42 pmHi :
May 20th, 2009 at 7:32 amI have successfully cycled my 12 gallon nannotank and have just added 12 dwarf seahorses in the aquarium. It has been setup now for 5 weeks.
The aquarium has red algae/slime which is now almost completely covering my merman’s shaving plants and live seafans, the local fish stores here in South Florida all recommend I use chemicals to get rid of the red slime. I puchased a red slime rid but I am hesitant to add any to the tank with my dwarfs.
I have not done a partial water change yet waiting for the nitrifying bacteria to become fully established.
I would appreciate your recommendation.
Thank you,
David E.
Red slime algae (cyanobacteria) is generally a sign of high phosphates in the water. They are harmless except that they can fuel algae blooms, as you’re now seeing. There are a few ways you can reduce nitrates. Water changes are probably the best way, but if you’re not finished with the cycle, I can see why you wouldn’t want to. Chemical means are another way, phosphate removers, or general pads for removing organics will work too. They are usually in a pad or gravel form to be put in a filter.
Red Slime removers, what you were recommended, work too, but they have to be accompanied by a water change anyway. They also can be hit or miss. And you do here rare accounts of tanks crashing when its used.
I’d personally do water changes, you’re probably not going to take out enough water to remove all the ammonia and nitrite to really make a difference, but you can start removing phosphates. Also consider using RO/DI water to make your salt water if you’re not already – a lot of phosphates come from tap water.
May 20th, 2009 at 10:14 amWell, my red slime is gone and I just want to say a word about Cramer’s Caribbean Critters.
June 1st, 2009 at 8:59 amDana is wonderful to deal with , he packs everything professionally and he backs up with action everything he states to the customer.
I had a yellowhead jawfish arrive doa, Dana immediately replaced the loss.
Unlike other collectors of dwarf seahorses I have dealt with, Dana responds right away by phone and email, giving his professional opinion on compatibilty of marinelife. I will only buy from Cramer’s Caribbean Critters from now on.
Dana is a true professional and I highly recommend him to anyone wanting to purchase marine fish and invertebrates.
Thank you,
David Ellenberg
Good morning Aquagirl:
June 15th, 2009 at 8:06 amI have noticed that my rock surface are covered with the white hydroids, some of my dwarfs were lost in the last few days, I do not know if they came in contact with the hydroids or another reason.
The problem I have is I also have some beautiful tubeworms and gorgonias as well as snails, anemonoe shrimps and I am adverse on placing chemicals into the water , I did get rid of the red slime with it.
Are there any natural preditors that would eat the hydroids with no harm to the dwarf seahorses?
If not, is there a chemical cure that will rid the tank of hydroids without harm to the inverts? That is reef safe?
Thanks very much for your help!
David
Enough hydroids can kill even adult dwarves, but a bigger potential problem is depriving them of food; a large colony of hydroids can quickly consume all the food in a small aquarium. And the more you feed, the faster they grow.
The only thing I know of is a hydroid eating nudibranch. I personally don’t have experience with them, but Dana at CCritters sells them – well, I did get one for my reef, and it seemed to immediately be drawn to the hydroids, but fell into a near by ricordia after about 10 minutes in the tank and was killed, so they must be very sensitive.
I also suspect it will take time for nudibranchs to consume all the hydroids. If you try them, I’d try a couple, and even before introducing, scrub where the hydroids are and syphon as you go – a second person to help would be handy.
If you try them, please let me know how they work for you!
June 16th, 2009 at 5:41 amHi there – VERY good article!! I just wanted to give a word to the one asking about a watchman goby… Mine lived with my 1 year old full grown NON-dwarf seahorse (hippocampus comes) for almost a year before he started head-butting & killing everything, including the seahorse ; 0 (
He is the boss, the king, etc.
They are nice & cute when they are small – (freaking adorable really)but mine went from 2 inches to 9-10 inches in a year!! I still can’t catch him to donate to the zoo like I want to!
I would like to know what you think about me putting 4 dwarves in the 10 gallon with my mandarin & emerald crab (only occupants besides pods). I have been testing her by turkey ‘bastering’ amphipods near her – and she leaves the 1/4 inch pods alone – only goes after the teenie-tiny ones, plus a have a huge copepod population…
June 20th, 2009 at 5:29 pmThis website was very helpful!!!
July 4th, 2009 at 4:33 pmIs shipping alot if you buy something from this site?
July 4th, 2009 at 4:34 pmjust wondering, is it possible to keep dwarf and the bigger breeds of seahorses together in the same tank considering that the tank is going to be a big enough tank.
And also if the dwarf’s do breed do the babies need to be kept separate from the bigger seahorse breeds?
September 2nd, 2009 at 12:28 amDear karina i Wouldnt advise keeping them with bigger seahorses because bigger sea horses eat Bigger brine and may eat the tiny dwarfs also the fry can stay in the tank with mum and dad . But if you dont like that idea you can have a bare bottomed tank with nothing but a few small artificial plants. if you choose to do this your tank must be readily cycled Id advise A five gallon would be perfect for you new fry. I for one leave my kiddies in the tank with mum and dad be cause its so easy for the young to get hurt or bruised in the transfer. I dont know what species and size your other seahorses are Because dwarfs full size are only 1 inch long. And Most other horses grow at least 6 or 7.
September 2nd, 2009 at 2:50 pmI have to agree, mixing larger seahorses and dwarves isn’t a good idea. In addition to the above, you run the very likely risk of not being able to keep food density high enough in a large tank, so the dwarves would slowly starve. I’ve also heard reports of people trying it and the large seahorses having problems with the baby brine shrimp irritating their gills.
September 2nd, 2009 at 11:01 pmkool, i didnt know that, you do learn something new every day. I think i’ll stick to just dwarves for now. we’re going tonight to get a new tank even tho we hav a million sitting around the house, and I’m gonna use water from my bf’s tank so it’ll speed up the process and I can get my little dwarfes sooner
Is there any specifics they need in their environment
September 2nd, 2009 at 11:04 pmSome artificial plants they can hitch on would be good. Avoid live rock, too many dangerous hitch hikers. Stick with a sponge or other air powered filter and you’ll be all set.
September 2nd, 2009 at 11:58 pmoh yeah!, that something else i wanted to ask. what would be the best kind of filter to use? my Bf asked our local fish shop and one of the guys who had just set up a seahorse tank said a gravel filter, but I’ve read these arent good to use in with the dwarves???
any suggestions? :/
September 3rd, 2009 at 12:06 amA sponge filter is best, like this:
Sponge Filter
You’re right to steer away from a undergravel filter. For one, never use gravel in a marine aquarium!
September 3rd, 2009 at 12:19 amthanks for that.
I was thinking of using crushed coral which i heard is the best?????
Good idea or…. ? :S
September 3rd, 2009 at 12:22 amCrushed coral is too course and waste will get trapped there. Sand for marine aquariums is a much better choice, like aragonite stand.
September 3rd, 2009 at 12:24 amok, kool.
September 3rd, 2009 at 12:27 amalso how loud is the filter, i’m considering putting it on my bedside table so its in my room so its RIGHT next to me?
I have two aquariums in the bed room, and they don’t bother me, including one air powered. However, they took a while to get used to, so I wouldn’t recommend it if you’re a light sleeper or if expect the bubbling from the filter or vibrating from the air pump to keep you up.
September 3rd, 2009 at 8:38 amyeh im not the best sleeper haha
.
September 3rd, 2009 at 8:43 amalso i thought that you cant have bubbles in their aquarium coz they cant get oxygen in their gills/airways…
That is an old wives tale that still persists today. It comes from seahorses being prone to a condition called “Gas Bubble Disease” and people once assumed that came from actual air bubbles. However, that is not the case, the disease is an internal chemical balance issue. Also, don’t worry, dwarves are rarely stricken by it.
September 4th, 2009 at 5:00 amThe site you reccomended to me cramers caribbean critters, Do they ship to Australia??
September 7th, 2009 at 8:18 pmI don’t know, but I would suspect not. Shipping seahorses across international borders is an expensive prospect that requires the proper permits.
September 10th, 2009 at 8:10 amWhat is (in your opinion) a good size tank to hold a pair of dwarfs and eventually their babies?
November 4th, 2009 at 3:36 pmI would get at least two pairs, dwarf seahorses do better in groups. With two pairs, I would start with a 2.5 gallon aquarium.
November 10th, 2009 at 7:44 am.-= aquagrrl´s last blog ..Protected zones will help to save Britain’s marine wildlife =-.
Hi
About ten years ago I was in a pet shop in Washington MO where they had a ten gallon tank packed with dwarf seahorses all sizes and they were feeding frozen baby brine and they seemed to be doing great was that a freak deal? Because all i have read is that they have to have live brine. any thoughts?
November 20th, 2009 at 4:51 pmHi there – I just wanted to say that I recently purchased a nudibranch (Nudibrach learchis poica) from ccritters.com, it was extremely cheap (2.50) and had ALL the hydroids eaten out of the 5 gal in less than 48 hours!! DID NOT bother the dwarves at all! Luckily I have other tanks for it to work in -(and I am secretly hoping some grow back so I can keep him) but when they run out I will probably let it clean up the 5 gal again, then find someone on craigslist with a hydroid problem.
I know there are some serious dwarf lovers over here – so I just had to tell you that didn’t already know!
December 21st, 2009 at 5:19 pmHI Ryan – I have a thought! I think I am going to thaw some frozen out and add it the same time as the live – and try to trick them!! As a matter of fact – this is how I got the mandarin to eat frozen mysid/mysis, and eventually I didnt have to worry about copepods or amphipods!
December 21st, 2009 at 5:21 pmWhat type of corals/ seafans can i keep with dwarfs?
January 30th, 2010 at 9:44 amIf i keep a firefish goby with dwarfs in a ten gallon, would i still need 20 seahorses, becausethe firefish should eat the brine shrimp? Me confused.
February 1st, 2010 at 12:00 pmWhat about a firefish goby, 2 pugnose pipefish, and What # of seahorses?
February 1st, 2010 at 12:02 pmalso http://www.seahorsecorral.com is a good captive bred seahorse dealer.
February 1st, 2010 at 12:49 pm