Fish are complex beings. The evidence is piling up that not only are fish sentient, they also feel pain and are able to carry out complex tasks.

What are some of the problems with aquaculture from an animal rights perspective? Why is CO2 stunning, a common stunning method still legal in Norway and Finland, a welfare problem? How do fish feel pain?

These questions and more are answered by Dr Lynne Sneddon, Director of Bioveterinary Science at the University of Liverpool.