Food-satiated goldfish were stimulated in tanks containing food on the surface of the water and on the bottom of the tank. Various components of the feeding response were seen, and complete feeding was observed, which was elicited from sites in the postero-medial hypothalamus. Evidence is put forward to support the supposition that the full response was due to a change in feeding motivation, rather than to changes in sensory or motor factors. Other types of behaviour, such as fin movements and swimming, could not be identified as part of any normal ethological sequence. However, vertical movements and gas-spitting responses indicated a possible hypothalamic control of buoyancy. None of the behaviours observed was seen to change in a social context.