seahorses are very easy to keep. Have many myself. Water quality is a must. ANY nitrite or ammonia and they are dead. Live food is not necessary, but they do much better with live mysis. Sachs aquaculture in Florida has the best prices I have seen. I get weekly drop shipments. Tank must have great water flow, very few dead spots, and peaceful tankmates. A lot of people try to keep clowns or gobies ect, but they still compete for the food source, expecially if it's live. i use a clear plastic trap, the horses get used to it, and will swim right into it, I put the food in, they eat what they want, then I release them. I always have lots of live mysis shrimp in the tank, along with LOTS of pods. Horses will change color due to mood, or colors in tank. I was reading someone elses remarks about having lots of medicine for them. THIS IS A MAJOR NO NO. NEVER GIVE ANY FISH ANY TYPE OF MEDICINE. If you have to medicate your fish or your tank, there is another problem, and its not the fish. If you slowly lower your salinity down to 10-15 (specific gravity to 1.008-1.012) your tank will NEVER get sick. I know what people are saying "OH my god he's nuts". Everything will survive, and thrive. All fish, corals and inverts will do just fine and reproduce. When you lower the gravity and salinity, it raises the allowable oxygen levels. No parasite can survive in the hyposalinity. The colors of your fish and corals will explode. They will eat more, and grow and reproduce faster. I have been doing this for nearly twenty five years, it works, and works very well. I have NEVER lost a fish due to disease.
Dont go do a massive water change overnight and drop your salinity, it will cause shock. (think this is a no brainer, cant tell you how many morons due just this, even at your local fish store). If your salinity/gravity is around say 35 and 1.022, next time you do your 10% water change, use water with the gravity of 1.010-1.015 and do this every change there after. This will SLOWLY bring the levels down. Try it it woks wonders.