Red and blue Basculin get along so poorly, they’ll start fighting instantly. These Pokémon are very hostile.
Red and blue Basculin usually do not get along, but sometimes members of one school mingle with the other’s school.
Red- and blue-striped Basculin are very violent and always fighting. They are also remarkably tasty.
Savage, violent Pokémon, red and blue Basculin are always fighting each other over territory.
When a school of Basculin appears in a lake, everything else disappears, except for Corphish and Crawdaunt. That’s how violent Basculin are.
— Pokédex entries (via PokeAPI)