Talk:Fishes/@comment-10404182-20191109225208

It may sound weird, but there's no such thing as a fish. "Fish" is just a colloquial term. All those animals that we call "fish" are actually from separate classes (sharks and rays belong in Chondrichthyes, ray-finned fishes belong in Actinopterygii, coelacanths and lungfish belong in Sarcopterygii, lampreys are their own group and the same goes for hagfish). Basically, a shark and a tuna are distant from each other more so than a lungfish and any land vertebrate are distant from each other.

Scientists now classify birds as dinosaurs and whales as ungulate mammals due to their ancestry, but they still don't call mammals, reptiles, or amphibians "fish" because there is no particular group or class called "fish".