Behavioral Characteristics of Adult Zebrafish (Danio rerio) after MS222 Anesthesia for Fin Excision.

The health of laboratory animals is an ethical responsibility of researchers and a critical determinant of experimentaloutcome. Therefore, all husbandry procedures should be evaluated for their effects on mortality, behavior, and physiologyto maximize animal welfare and minimize experimental variability. For adult zebrafish, the excision of a small portion ofthe caudal fin (that is, 'fin clipping') under MS222 anesthesia is a common procedure to obtain tissue for genotyping. Thepotential effect of this procedure on behavioral and physiologic assays of feeding, anxiety, and stress has not previously beenassessed. Here, we evaluated feeding behavior, anxiety-associated behaviors, and physiologic indicators of stress at multipletime points within 24 h after performing a standard fin-clip procedure under MS222 anesthesia. Within 1 h of the procedure,fin-clipped fish showed a mild increase in anxiety and exhibited reduced feeding; however, these effects were short-lived,and the fish exhibited baseline levels of anxiety and feeding by 6 and 24 h after fin clipping. Together with the zebrafish'sability to regenerate fin tissue and the low mortality associated with fin clipping, our data support the continued practice ofthis technique under MS222 anesthesia as a routine husbandry procedure that is unlikely to alter experimental outcomesrelated to feeding, anxiety, or stress.