“I am a fish”, is this due to the fish ancestry of tetrapods with very similar bone structure? The gills became the modern ear…I believe. Fins became limbs with digits, we did lose the lateral line system but we gained access to land.
Ding ding ding ding DING! We have a winner!
‘Fish’ is, strictly speaking, not a taxonomically meaningful category. Tetrapods – that is, all amphibians, reptiles, birds and mammals – are descended from lobe-finned fishes, an incredibly ancient class of fishes that includes the coelacanth. This means a) that the coelacanth is actually more closely related to humans than it is to salmon, goldfish, etc, and b) that, in the same way as all birds are dinosaurs, all land-dwelling vertebrates really should be considered fish. The fact that they’re not is really just due to the scientific community choosing to bow to common sense in this instance.
If that paragraph made sense to you, you should probably be able to appreciate why asking “are Pokémon animals?” is actually a fiendishly intractable question.