system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How come shrimps are pale and semi-translucent when raw, but when cooked are turned red?

This goes for lobsters and crabs, as well.
gpt
It's a pigment called Astaxanthin!  It's red, and is present in the shells of those crustaceans, as well as in fish like Trout and Salmon, which is why those fish are reddish-pink as well.  As for why Crustaceans don't turn red until you cook them, that's because in their shells Astaxanthin is bound up in other proteins.  When you cook them, the heat begins to denature these proteins and the released Astaxanthin suddenly becomes apparent.