Starfish' is a misnomer. They aren't really fish. A bit like the word 'pineapple'(neither pines nor apples) or guinea pig(not from guinea, not pigs). Starfish are invertebretes which are very much different from fish. read more
Taxonomically, the phylum includes the following subphyla: the Vertebrata, which includes fish, amphibians, reptiles, birds, and mammals; the Tunicata, which includes salps and sea squirts; and the Cephalochordata, which include the lancelets. There are also additional extinct taxa such as the Vetulicolia. read more