The many stages of Linnaeus begging for food. He loves to be hand fed algae wafers! For those of you unfamiliar with Linnaeus he is a West African Lungfish (Protopterus annectens). Unlike most modern fish which are in the class Actinopterygii (this includes 99% of fish spp), lungfish and their distant cousins the coelocanths belong to the class Sarcopterygii. This is the class that gave rise to the first tetrapods, so lungfish have some very odd physical characteristics for a fish. This includes teeth coated in true enamel, lungs homologous to tetrapod lungs, and a four chambered heart.