Warm-blooded Fish?

Ben can't sleep.

Dad, are corals warm or cold blooded?
Wikipedia has a lovely diagram. Coral don't have blood, they have a jelly like diffusion substrate.
Go to sleep Ben.

Dad, are there warm blooded fish?
Slashdot (of all places) says yes - sort of. The North Pacific Salmon Shark is particularly impressive, but many fish have various ways to use heat to improve performance. They don't, however, have the same obligatory temperature constraints we have.
Go to sleep Ben.

This is fun.