sounds weird.. ethical behaviour is always associated with humans. but here, cleaner fish have been punishing their friends who make mistakes.
you see, this fish, bluestreak cleaner wrasse is one of those fishes that clean larger fish. both the males and female clean the larger fish, working as a pair. eating up dead cells, picking out parasites and such.
but once in a while, the female fish tries to get a go at the mucus on the larger fish’s skin (which for some reason taste better). the larger fish doesnt like this, and will often swim off in a fury. when this happens, the male fish also loses out on a proper meal.
to ensure the females dont go beyond what they are supposed to eat, male fish will aggressively chase the female. this threatening act supposedly teaches the female a lesson, which reduces the chance of them inappropriately eating fish skin mucus the next time.
so funny. individual gains driving the rationale for moral behaviours… haha..