Our favorite small aquarium for most people is the Fluval Flex 9-gallon Aquarium Kit, which includes everything your new betta, shrimp or school of small fish needs for a long and stable life.

Best fish tank light: Current USA Satellite Freshwater LED - See at Chewy Current USA's ultra-thin, ... "It is harder to keep a small fish tank than a big fish tank," said Hwang.

Too small, and it won’t process waste quickly enough. Too big, and you risk crowding the tank and exhausting your small fish. Here are the best filters that find that perfect middle ground.