Also known as: 鱼之恶魔, 魚の悪魔
The Fish Devil is a devil who embodies the fear of Fish.
Fish Devil has the appearance of a giant fish, with twin tails at its back end. Its only other distinguishing feature is its set of 6 seemingly bio-mechanical legs.
At some point, Fish Devil had eaten a chunk of the Gun Devil (Chainsaw Man)'s flesh.