The effect of cystamine on crayfish behavior. After injection, the behavior of the individual crayfish in each group was recorded in a 3-min video at 3, 6, 24, 48, and 96 h. The pictures show in still frames from a video used to determine the different activities of crayfish after cystamine injection. The activities of crayfish in each group were compared with CPBS injected crayfish as a control. The crayfish behavior was analyzed based on their mobility, immobility, aggressiveness, and activities. 20 crayfish were used in each of these experiments.