how to take care of a siamese fighting fishWhen reinforcement followed every reaction and when reinforcement was brought after every second response, the number of responses per session was higher than during operant level or during extinction. Reinforcement brought following durations of no responding differential reinforcement of alternative conduct markedly decreased responding. Light from a projector without film was found to be as positive a reinforcer as film reinforcement. Responding when projector light reinforcement followed every reaction was maintained at about an identical level as that acquired under film reinforcement. Responses per consultation decreased when only the sunshine was introduced on a differential reinforcement of alternative behavior agenda. The behavior of the fish during presentation of the film was markedly various from their conduct while the projector light was being provided.