It's a difficult line to place, for instance is pain avoidance plus memory enough? If I imagine a fish thinking "I can't do that again" that certainly looks lik

It's a difficult line to place, for instance is pain avoidance plus memory enough? If I imagine a fish thinking "I can't do that again" that certainly looks like sentience, but the resulting behavior (avoidance) can occur without sentience, it seems. Is something like that been demonstrated in other animals?