WRONG.

I found a mistake on one of my GED study cards.

Octopuses (which is actually a more accepted form of the plural than octopi) are not fish. They are shell-less molluscs in the class Cephalopoda.

THEY DON'T EVEN HAVE A SPINE HOW COULD THEY BE FISH...?

I love it when all my seemingly useless knowledge comes in handy.