I’m curious what evidence convinced you about fish. So far I haven’t seen much on the subject of consciousness specifically, though I have seen some arguments around pain nerves and aversive stimuli.
Victoria Braithwaite, who wrote the book Do Fish Feel Pain, said “Given all of this (the evidence she and other researchers gathered), I see no logical reason why we should not extend to fish the same welfare considerations that we currently extend to birds and mammals.”
There are a number of studies on fish that provides evidence of consciousness beyond just nociception and pain avoidance behavior (which is already a level higher than just nociception). I will just name a few. Most recently and shockingly, a species of fish passed the “mirror test” by passing the “mark test”. Other older studies include finding that fish engaging in trade-off thinking between rewards and pain, finding that fish engage in cooperative behavior, and finding that zebrafish can have “emotional fever” (which scientists used to think can only happen to birds, mammals, and reptiles)
Victoria Braithwaite, who wrote the book Do Fish Feel Pain, said “Given all of this (the evidence she and other researchers gathered), I see no logical reason why we should not extend to fish the same welfare considerations that we currently extend to birds and mammals.”