The Siamese fighting fish (Betta splendens), also sometimes colloquially known as the betta, is a species in the gourami family which is popular as an aquarium fish. Bettas can be territorial fish and are prone to high levels of aggression towards each other. Two males in close proximity will almost always attack each other, if they do not have the ability to escape this will usually result in the death of one or both of the fish. Female bettas can also become territorial towards each other if they are housed in too small an aquarium. It is typically not recommended to keep male and female bettas together, except temporarily for breeding purposes which should always be undertaken with caution.