The handling of fish and other aquatic animals in and out of their natural environment is always very difficult. Their struggling has strong effects on their physiology and behaviour and the animals can easily be damaged. Anaesthesia and sedation are therefore essential techniques in fisheries management and aquaculture to minimise stress and physical damage caused by crowding, capture, handling and release. It is also essential in veterinary practice and research work. Sedation of dangerous aquatic animals such as crocodiles is necessary also to protect the handler. This handbook draws together in a practical and accessible form the available information on sedation and anaesthesia of fish and other aquatic animals. Temperate and tropical freshwater species are considered as well as sedation in sea water.