Fish that are kept in home aquariums. Good places to buy fish are non-chain fish stores; there will usually be several in any given city. Beware, though, since some storekeepers do not care about the hobby of fishkeeping and will only give you bad advice in an attempt to sell you merchandise that you don't need. Wal-Mart is a very bad place to buy fish since no one there knows jack shit about fishkeeping. Pet's Mart at least hires psuedo-competent people, but they never remove diseased stock from their tanks. Try not to buy diseased fish unless you really know what you're doing; even then, it's generally a Bad Idea. Another Bad Idea is buying a fish that you know nothing about - you might accidentally kill it because you don't know its water requirements, or it might eat your other fish.