Schooling

If this Pokémon is a Wishiwashi and level 20 or above, then when it enters battle and at the start of each turn, it becomes Schooling Form if its HP is 25% or higher and Solo Form otherwise. This ability cannot be replaced, copied, or nullified.

“When it has a lot of HP, the Pokémon forms a powerful school. It stops schooling when its HP is low.”