Is a fish cold blooded or warm blooded?

Answer 1

It depends

Answer 2

It depends on the fish. Most fish are cold blooded, but a few are not. Several species of tuna, for example, are able to maintain their body temperature within large range but above the temperature of the water around them.

Well Actually, bluefin Tuna and some other species are neither warmblooded nor coldblooded. They are species in between, meaning that they selectively warm parts of their body.

Also the Tuna does not spend energy to keep warm like warm blooded animals, it just has two specific sets of thin blood vessels that work as heat exchangers. One close to the brain and one close to the tail. The tail heat exchanger warms the blood coming cold from the gills, by passing it next to the warm blood, going from the hot tail swimming muscle to the gills.
Almost all fish are cold blooded. However, some species of Tuna are able to maintain a body temperature above the ambient seawater temperature using a special organ called the 'rete mirable'.

Answer 3

cold blooded

Answer 4

They are cold blooded.