or, alternatively, a fish bonds with the fisherman in that short but precious period between it being caught and on its way to the holding tank. It takes just that one glance and the fish knows "nah, brah. It's cool, you'll be good to me".
Same thing with clams, oysters, mussels, scallops, shrimp, lobsters, chickens, turkey, ducks, etc.
And this does not count as your proof