IME I have found that seahorses are not diffucult to keep if given the proper setup and care. the setup does vary from a traditional reef tank or FOWLR system.
In order to keep the medium to large size seahorses I would recommend a tank at least 29 gallons or larger. You could go with a tank as small as a 15g but for your first system you will want to have a bit of a cushion and the option of purchasing an additional pair down the road without having to purchase an entire new system. Trust me once you get a seahorse, you will want more.
The parameters for a seahorse tank are very similiar to a normal marine setup. You will want your ammonia to read 0, your nitrites to read 0, your nitrates to read 0 but <20 is acceptable. The PH should be 8.0 to 8.2, the Salt gravity 1.022, temp 72-75F.
It is best to keep the temperatures for seahorse tanks lower to help slow the growth rate of bacterias that will lead to infections. Research has shown that the bacteria will reproduce at a slower rate which is better for the seahorses.
The flow for a seahorse tank is also quite different from a reef system. You will want to keep the flow between 3x and 5x the tank volume turned over each hour. That means if you have a 30g tank you will want your flow to be between 90 and 150 gPH (gallons per hour).
The reason for the lower flow is because seahorses are not strong swimmers, ( H. abdomonalis are, but they are a temperate species and a bit harder to care for). Strong currents will easily push them around the tank causing stress at the least and often injury. Strong currents also make it diffucult for the seahorses to catch there food to eat, so overall you want to keep your flow down.
IME it is possible to have more flow in a tank if the flow is broken up so that there is not one large area of flow but several weaker areas of flow. A spraybar is a great way to accomplish this. It will allow you to increase the flow in the system, while still keeping it seahorse friendly.
For biological filtration both liverock and livesand can be used. Both should be fully cured before entering the tank. It is a good idea to check the rocks for aiptasia, as the sting from an aiptasia is strong enough to kill a seahorse. I usually like to start with at least 1 lbs of LR per gallon of water. Tonga branch rock is my favorite because it also doubles as a seahorse hitch. I like to keep the sand bed 1" or less. DSB while they can be used in seahorse tanks take away some of the vertical swimming room (how much depends on the system) which seahorses really utitlize especially during courting.
Typically when I cycle my seahorse tanks I cycle with pure unscented ammonia. The variety I use is 10% and I use a formula of .5ML per 10 gallons of water. So in a 20g tank I use 1ML, in a 30g 1.5ML etc. I feed the tank the ammonia every day up to a few days until I get my seahorses.
The feeding of the ammonia directly to your tank allows for the biological filtration to fully take effect. the biological filtration works by various bacterias that grow. These bacteria's break down the ammonia and begin the nitrogen cycle. It is important for your tank to have enough bacteria built up in it to handel the large bioload of seahorses.
Another common type of filtration is mechanical. To give real good advice on what kind of mechanical filtration is best for your particular setup you will have to determin how large of a tank you wish to have, and whether or not you will utalizing a refugium or sump system. I have always been partial to te cannister filters myself but there are many quality filter choices available to the hobbyist.
A refugium, UV, and potein skimmer (you need to place a skimmer in a sump on a seahorse tank and not directly into the display system. Having skimmers empty directly into the display as shown to increase the likelyhood of gas bubble disease in seahorses) are all other filter options, while they are good to have, they are not needed for succsess.
Lighting for a seahorse tank is not diffucult. They only need enough light to see there food. Ambient room light is plenty. NO flourscents are also fine. If you wish to keep corals you can use whatever light you desire, just make sure the light is far enough off the top of the water so the temperatures can stay in the lower spectrum. Personally on my seahorse coral tank I have a mixture of T5 and PC lighting for a total of 348W, but I have also kept sytems with no lights.
That takes care of all the equipment you will need. Now on to the fun stuff, the seahorses.
There are many types of seahorses currently available. Erectus, reidi, barbouri, and kuda are all available CB speceis readily available. There is a tricky thing about purchasing seahorses, you have to be very careful who you buy from. Many of the seahorses on the market to day who claim they are CB are actually maricultured (raised in big nets in the ocean). These maricultred seahorses while not technically wild caught are exposed to the same number of parasites as a wild caught seahorse would be. It is commendable that they are not plucking the seahorses out of there natural habitats, but the quality of seahorse from these facilities are not on par with a true CB seahorse. Unfortunatley most of the CB seahorses available on the market today, are these maricultured seahorses. Seahorsesource.com and Draco Marine both currently breed seahorses in closed system true aquacultured facilities. I would strongly urge anyone intrested in seahorses to contact one of these tobreeders directly and not go through a middel man. Make sure you gt what you pay for Cb doesn't mean what it used to.
You will want to get all of your seahorses from the sae breeder if they aregoing into the same tank. It is not advisable to mix different species of seahorses together unless they were mixed as fry at the breeders. Seahorses are known to be asymptomatic carriers of various strains of vibrio, and can easily infect other seahorses without the same resistance. (the discovery of this and of parasites in the digestive track have made great improvements of the succsess rate of seahorses)
True Cb seahorses will arive eating frozen mysis shrimp. Find out what brand your breeder is feeding the seahorses and make sure you have a source and some on hand, before you buy your seahorse. Having food for them to eat is always a good thing.
As a precaution it might be good tostock up on your medicine cabinet before you get the seahorses incase anything ever goes wrong. There is a site aquabiotics.net that sells meds for seahorses with correct dosage for seahorses.
There are many corals you can succsessfully keep with seahorses, You will need to stay away from any coral with a sting, or that needs stronger current.
There are also a ton of fish you can keep with seahorses. Nothing to aggressive, stay awya from fast swimmers that will cause stress to the seahorses. Goby's are very popular choices.
Popular cleanup crews in clude various snails and scarlet reef hermits, other crabs have proven problamatic to several keepers.
If you have any other specific questions please feel free, I'm not around here to much but do come back often. Good Luck.
