we have a winner here!

Rorschach is either a panther grouper or a clownfish (as when Walter)
Doctor Manhattan is a bluefire jellyfish
Silk Spectre II as a tiger shark
The Comedian is a goblin shark
Ozymandias for some reason make me think of the bettafish

I gonna admit I don’t have a fish for Nite Owl, Daniel is so into owls I really can’t imagine him being anything else