Laboratory fish: impacts of pain and stress on well-being

The issue regarding the capacity of fishes to experience and suffer pain remains unresolved. Some argue that because the fundamental structures that are involved in pain perception and experience in mammals are not found in fishes, there is no potential for these animals to experience pain. Others believe that because fish demonstrate strong avoidance behaviors to noxious stimuli, other neurosensory processing systems to process pain information (yet to be identified) may have evolved and that the possibility for pain perception exists. Further work regarding the neurophysiological mechanisms and behavioral responses involved in nociception and potential pain perception in fishes is required and a practical set of indicators for well-being, such as easily identifiable morphological and behavioral cues, would be of value for the care and management of these animals (24). Apart from the ethical obligations of the investigator and those involved in the care of experimental species, the welfare of fish in an experimental setting is key to the quality of the research. Although there remains many unanswered questions, the wellbeing of these animals is a significant factor to quality science. Ensuring optimal environmental conditions in a minimal-stress environment is the best means for accomplishing that goal.