Bim

Bim is a shark fiend and demon hunter from the Fourth Special Division of Tokyo. Possessed by the Shark Demon, Bim is a young man with sharp teeth and a shark-like head covering his eyes. Bim lacks human features; he has two fins that function as legs and, consistent with his partial transformation, three pairs of eyes and sharp, spike-like fins on his upper body.

During your fishing trip you caught a shark with three eyes

You place the shark on a special platform separate from all the fish.

Then at night you went outside and you heard sounds from the side of the net, you came up and saw a man in the shark's place