No one knows precisely what causes this variation, but biologists believe the strange green or blue hues indicate that the lingcod have consumed a diet rich in chlorophyll, eating more plant matter—green algae through small crustaceans—than the rest.

Why do some lingcod turn blue?

The cause of this rare turquoise color is due to a bile pigment called biliverdin, which is responsible for turning the blood serum of these fish that freakishly odd color – but how this pigment gets into the tissues and flesh of the fish, or why only some lingcod turn this striking shade, still leaves biologists ...

Can you eat blue lingcod?

The lingcod is a popular eating fish, and is thus prized by anglers. Though not closely related to either ling or cod, the name "lingcod" originated because it somewhat resembles those fish. Around 20% of lingcods have blue-green to turquoise flesh. The colour is destroyed by cooking.