Cleaner fish are used extensively to remove sea lice in the Norwegian salmon aquaculture. These fish are removed from their natural habitat and placed into fish farms where environmental conditions may be outside of their normal ranges. This has raised concern about their welfare within sea cages. My research aimed to measure the effect of temperature on physiological performance in the Ballan wrasse (Labrus bergylta). My results will be used to produce welfare guideline for their use in aquaculture. Jeffrey moved to Norway as a research assistant at the Institute of Marine Research.