Hack

Japanese name:	ハック
Nickname:	Hundredth Dan

Hack is a fishman, with yellow skin, that has brown spots on the upper part of his head, along with scales under his eyelids, sharp teeth, and gills on the sides of his neck. The fishman has a muscular stature, with long light blue flowing hair and a thick blue moustache.

Similar to Kuroobi, he wears an open gi with a black belt.

onepiece.wikia.com