The zebrafish are housed in a purpose built Home Office accredited fish facility. The fish are housed in techniplast (TM) tanks at stocking densities of 3-10 fish per tank. Individual fish may be identified with the aid of elastomer tags (NorthWest Marine Technology Inc.). Fish husbandry practices (water parameters, nutrition and health surveillance) are in accordance with published guidelines (http://zebrafish.org, RSPCA 2010). Zebrafish will be filmed following tail fin clipping. The fish will be anaesthetised by immersion in MS222 (tricaine methanesulfonate). The caudal (bi-lobed) part of the tail fin will be resected using a scalpel blade or sharp scissors. The fish will then be returned to holding tanks and either housed singly (as is standard procedure following fin clipping for identification purposes) or in groups (in order to assess changes in social behavior which might be associated with pain). The behaviour over the following 6-12 hours will be recorded and analysed with the aid of computer tracking software. The same recordings will be used to measure physiological parameters (such as operculum/respiratory rate). For the cortisol assay, the tank water will submitted for cortisol level assays after 24 hours from fin-clipping. A second group of fish will undergo a similar procedure as described above but will be provided with analgesics (opioids e.g. morphine or NSAID e.g. fluribiprofen) systemically in bathing water or topically on the wound. To validate this model the behaviour of the above fish will be compared to three control groups: a group of fish anaesthetised but without undergoing fin clipping, a group of fish anaesthetised and fin-clipped and a group of fish exposed to analgesics but without fin clipping. Similar treatment groups will be used in the behavioural tests using environmental enrichment or novel objects.
Reference: RSPCA report (2010) Guidance on the housing and care of zebrafish, Danio rerio.