Only in Ultra Sun & Ultra Moon
SOS Encounter: Vast Poni Canyon
Super Rod: Vast Poni Canyon (5%)
Surf: Vast Poni Canyon (35%)
Its base catch rate is 205 out of 255 (higher is easier); the catch rate calculator works out your odds with each ball. For the look, the best colour match is Poké Ball or Sport Ball.
Evolution: Corphish → Crawdaunt (Level 30).
Corphish in every game · Pokémon Sun, Moon, Ultra Sun & Ultra Moon interactive map (Alola)