My cichlid stopped swimming around? Just hides at bottom of tank?

Sitting at the bottom most of the time is normal behavior for many cichlids. Since you don't know what species yours is, it's hard to say more about it. There are an estimated 3,000 different species of cichlids, and probably 400 to 500 species in Lake Tanganyika alone, so obviously there is an enormous amount of variation within the cichlid family.