I usually get them mix but lets see. a 50 gallon for guppies. a 30 for danios, a 45 for angelfish, another 45 for danios, mollies, and platys together, then I have a betta in a one gallon tank that I made,another 30 gallons with africna chiclids (I always write this wrong), and I take care of my grandmas 45 gallon Oscars tank. and in process of buying a saltwater tank. ill be new to saltwater fish