Environmental habituation and sexual composition affect juveniles' shoaling activity in a cichlid fish ( <scp> <i>Pelvicachromis taeniatus</i> </scp> )

Group living is widespread in animals, and many fishes form shoals. Examining within-group interactions may contribute to the general understanding of dynamic social structures animals. The sex ratio a group has been shown influence grouping decisions can be expected affect behaviour at level. Behavioural experiments usually involve relatively short acclimatisation times, although establishment environmental habituation understudied. This study tests whether long-term experimental conditions shoal performance (activity parameters, density) responses shoals an acoustic-mechanical disturbance cue juveniles cichlid fish Pelvicachromis taeniatus via individual tracking. consisted defined hit against tank, which caused sudden noise water movement. We found that higher proportion females increases activity (swimming speed distance covered), suggesting female P. are more active than males. Furthermore, declined when habituated settings with time were grouped together, reflect intensified member familiarity. Moreover, behavioural changes after weaker individuals kept their longer familiar conditions. For prey species, lower might beneficial under natural due conspicuousness group. did not find any significant effects investigated factors on density (mean interindividual distance) synchronisation. results indicate sexual composition, familiarity between members environment fish.