Probably one of if not my absolute favourite fish. Gets to a reasonably size but a pair or trio can comfortably live in a heavily planted 10 gallon and will breed if conditioned properly. Their broad temperature requirements also means they can be comfortably kept in anything from near freezing water to tropical conditions. They are slightly territorial and can stand up for themselves but don't go out of their way to bully other fish, and are generally calm and quiet, making them suitable tank mates for most fish of a similar size. They have deceptively large mouths and are easily capable of swallowing slender fish up to 2/3 their length. They become quite personable and make a great "wet pet" for larger nano tanks.