PURPOSE: To obtain a method for developing bright red color on the body surface of crustaceans capable of showing a dark color on the surface of the shucked meat in a fresh state and other fishes and shellfishes having the dark color of a carotenoid-based pigment on the body surface while keeping the completely fresh state.

CONSTITUTION: The objective method for developing a color of crustaceans and other fishes and shellfishes by treating the crustaceans such as a shrimp, a lobster or a crab with a shell or free thereof and the fishes and shellfishes such as a cuttlefish, an octopus or a fish with an alkaline aqueous solution at pH 10-13 and developing a carotenoid-based pigment to red color.