The question of whether fish experience pain has been intensively researched over the past two decades, with a growing scientific consensus that they have relevant nociceptive capacities.
The scientific literature on fish pain has shifted substantially in the past two decades from skepticism to qualified acceptance that fish likely experience pain or at least nociceptive states with negative valence. Critics who argue fish lack the neocortical structures required for conscious pain are challenged by evidence that fish achieve similar functions through different neural architecture. The balance of evidence now supports a precautionary approach to fish welfare, treating fish as if they experience pain until proven otherwise.