I pretty sure most fish if not all fish feel pain. When my fish get ick it scratches itself with the gravel. That is a feeling that they can feel so why not feel the pain when they get hurt? When you watch 2 beta fight, you can tell if one is hurt by the way he is swimming and avoiding. Plus a bite cause the beta to squirm and squiggle. Would you call that pain? or call that sensation? I think sensation (feeling) come with pain.