Behavioural Analysis of a Nociceptive Event in Fish: Comparisons Between Three Species Demonstrate Specific Responses

Nociception is the sensory mechanism by which potentially harmful stimuli are detected in animals and humans. The behavioural responses to noxious stimulation have been studied in two fish species thus far. However, since species-specific differences are seen in mammals, more species need to be examined to determine whether nociceptive responses are generic in fish. The present study investigated the behavioural and respiratory response to an acute noxious or potentially painful stimulus in common carp (Cyprinus carpio), zebrafish (Danio rerio) and rainbow trout (Oncorhynchus mykiss). Behavioural parameters such as frequency of swimming, use of cover and any anomalous behaviour were measured along with ventilation rate before and after noxious stimulation in the carp and zebrafish. Although no differences in behavioural or ventilation rate response were observed between noxiously stimulated carp and control fish, anomalous behaviours of rocking from side to side and rubbing of lips against the tank walls were observed in two of the five fish. In contrast, zebrafish displayed a significant reduction in frequency of swimming and an increase in ventilation rate, which was similar to the results obtained from rainbow trout. Zebrafish did not display any anomalous behaviour. These dissimilarities in response to potentially painful stimulation demonstrate that there are species-specific behavioural and physiological responses to a nociceptive event in fish.