heres where i got most of my info from
http://www.seahorse.org/library/arti.../library.shtml
they even have a tank mates guide which rates suitability for horses, i have 3 in my reef and had to get rid of a couple corals that sting, it can be a little disappointing with the limitations on what you can keep but i would never get rid of mine, basicly no overly active fish, no stinging corals, low flow, lights are just for whatever corals you keep, sps sometimes dont do well if irritated by constant hitching (although mine do just fine), and make sure they feed well on a nutritious food source as they will need feeding often since they have a poorly developed digestive system, hope tht helps