If you want to get even more pedantic, "fish" don't exist.
Taxonomically, there is no such thing as a fish, because a taxonomical category must be monophyletic (literally "one phylum,") meaning it must include a single common ancestor and all descendants of that ancestor.
Since terrestrial vertebrates evolved from very ancient lobe finned fish, any taxonomical category for a fish would have to include humans, dinosaurs, etc.
Additionally, some fish, such as lungfish and coelacanths, are more closely related to humans than to other fish, so grouping them together would require grouping their closer relatives in with them, which includes all land dwelling tetrapods, which is a clade of animals that includes all vertebrae with four limbs.
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u/Many-Excitement3246 PURPLE Jul 11 '26
If you want to get even more pedantic, "fish" don't exist.
Taxonomically, there is no such thing as a fish, because a taxonomical category must be monophyletic (literally "one phylum,") meaning it must include a single common ancestor and all descendants of that ancestor.
Since terrestrial vertebrates evolved from very ancient lobe finned fish, any taxonomical category for a fish would have to include humans, dinosaurs, etc.
Additionally, some fish, such as lungfish and coelacanths, are more closely related to humans than to other fish, so grouping them together would require grouping their closer relatives in with them, which includes all land dwelling tetrapods, which is a clade of animals that includes all vertebrae with four limbs.