We are all fish; lobefinned fish to be precise. It's just that we have been (mostly) living on land the last 370 millon years.
Look! This has -2 as of today. I'm sure that downvoting this completely factual comment will change how we came to be here...
It's also a simple fact that a cod fish is more closely related to a human than to a shark. Does that then mean that we shouldn't call sharks fish?
"Nie jestem rybą, narkomani cholerni!"