Fish
There are several classes within the grouping Fish. If I were to give them equal standing within this website, the classes below would actually appear on the previous page alongside Mammalia, Aves, Amphibia, and Reptilia. To keep it simpler, I have grouped all the classes of fish here.
Class
Actinopterygii: Bony Ray-Finned fish (99% of all fish species)
Chondrichthyes: Cartliganeous fish (Rays / Sawfish / Sharks / Skates)
Hyperoartia: Jawless fish (lamprey)
Sarcopterygii: Bony Flesh-Finned fish (Coelacanth / Lungfish)