Temperature dependence of memory in fish

The influence of temperature on the retention period of a pattern discrimination task (cross versus triangle) was examined on Carassius carassius, Cichlasoma nigrofasciatum and Phoximus phoximus. After training at optimal temperature conditions the experimental subjects were kept at a 10 degree C lowered temperature, whereas for control subjects there was no temperature change. Tests, carried out every two weeks, showed a significant increase of retention for Carassius c. and Cichlasoma n.; Phoximus p. showed a slightly more rapid forgetting. These results and investigations of oxygen-uptake indicate a direct dependence of memory processes on the metabolic level.