by: Admin_LouisPosted on: ______is the part of fish that serve as respiratory organs in fish. ______is the part of fish that serve as respiratory organs in fish.Nostril—>> GillsMouthTrunk Share this:TwitterFacebookLike this:Like Loading... Related posts:_____is the part of the fish which fish scales are attached to.How many eyes does a typical structure of the fish have _____________is the type of unpaired fin that occurs below the lateral line on the lower surface of the trunk ?How many types of paired and unpaired fins are found in the fish body.