Blue tangs and most/all tangs would get to big for a 2 foot tank. Clownfish are fine in smaller tanks. You can't have seahorses with fish, as the fish will out compete them for food. Anemones and corals etc can be bought in pet shops, but make sure you have the correct lighting levels some corals require more light like acro's, mushrooms are fine under lower light. You can either use NSW or ASW, (natural salt water or artificial saltwater). Artificial can be bought at petstores, and you have to mix it with freshwater, others myself included use NSW, which is saltwater just collected from the ocean. I would reccomend you get a good protein skimmer though. And don't skimp on the cost :bounce: