3.3. Interspecific aggression
Fish practically performed no aggressive actions towards crayfish (only 6 recorded events of overt attack) whereas they frequently exhibited aggression towards conspecifics (3090 aggressive actions during all recording sessions, mainly overt attacks). Crayfish performed 212 aggressive actions interspecifically (mainly cheliped extending). Intraspecific aggression among crayfish was almost as frequent, totaling 186 actions. Interspecific aggression was more commonly addressed towards small fish, mainly by the dominant (size × rank interaction F1,49 = 6.3, p = 0.016; Fig. 5A). The vast majority of aggressive actions were performed after feeding (feeding × rank interaction, F1,49 = 5.0, p = 0.03; Fig. 5B).