Schooling in Pokémon Ultra Sun & Ultra Moon

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

Level 20+ Wishiwashi becomes School Form above 25% HP and Solo Form at 25% or less.

Wishiwashi at level 20 or above changes to School Form on entering battle or at the end of a turn if its HP is greater than 25% of maximum; at 25% or less it changes to Solo Form. Below level 20, it stays Solo Form. The Ability cannot be copied, replaced or suppressed.