Fast, fun, freaking fact.

The Barrier Reef Anemonefish. Very interesting creature, this one. Groups of this fish live in a single anemone, of the variety that is poisonous to other fish (but not to them). The group is dominated by the largest female. The second in command is the largest male. However, should the largest female perish (you know, perhaps being poisoned by a poisonous cone fish or something), the largest male steps up to the plate. But he doesn’t step up as a guy. Nope, he assumes her position by changing sexes. De-di-cation.