Indeed. That last one is definitely out, although I find all but the Mewtwo (and perhaps the Magicarp one) arguably fish-like.
Hey! Quite a few have been fish like 0~0"
Such as mine, WPS', Noobiess', Aclover's, and Moonlighting's.
Sea Snakes are a type of fish. Along with sharks. And Sea Horses.
The Mewtwo entry, along with the Flaaffy entry are the only non-fish like entries here.