Effect of previous fighting on the dynamic of agonistic encounters in zebrafish males

Recognizing the opponent: the consolidation of long-term social memory in zebrafish males

“…A previous study conducted in our lab suggests that zebrafish males show a significant decrease in their levels of aggression when faced with the same opponent in a subsequent encounter after a 24-hour interval (Cavallino et al, 2020). These results are in concordance with Miklósi and coworkers (Miklósi et al, 1992), who have found that paradise fish remember an opponent and change their behavior in a subsequent encounter against the same opponent after a 24-hour interval, but this effect disappears 7 days after the first encounter.…”

“…In order to evaluate if the reduction in the total time of aggressive behaviors observed in subsequent encounters (Cavallino et al ., 2020) remains for longer than 24 hours, 48- and 72-hour intervals were tested.…”

“…Following the same protocol of Cavallino and coworkers (Cavallino et al ., 2020), two size-matched adult zebrafish males from different community tanks were isolated in a small aquaria (2 L, 15 cm (high) x24cm (length) x9cm (width)). Individuals were separated by an opaque perforated barrier, which allows chemical but not visual communication, for 24 hours before the experiment.…”

“…Previous evidence suggests that zebrafish males show the ability to recognize a particular opponent, remember fight outcomes, and change their fighting strategies in a subsequent encounter against the same opponent, even after a 24-hour interval between fights (Cavallino et al, 2020). After previous experience against the same opponent, fish resolves subsequent encounters with reduced levels of aggression (number of bites and total time of aggressive behaviors), but this reduction is not observed if the subsequent opponent is different, suggesting a social memory formation (Cavallino et al, 2020). ( Our working hypothesis was that zebrafish males form a long-term memory associated with the first encounter.…”

“…In both sexes, intrasexual dyadic encounters usually start with a display (fish erects its dorsal and anal fins and flares its body flank toward the opponent) and it is followed by bites, circles (defined by two fish approaching each other in opposite directions and antiparallel position displaying circumference), and chases (when individuals actively pursuit each other alternately), until one individual wins the fight and chases the loser, which performs submissive behaviors as fleeing or freezing (Oliveira et al ., 2011, Scaia et al ., 2022). Previous evidence suggests that zebrafish males show the ability to recognize a particular opponent, remember fight outcomes, and change their fighting strategies in a subsequent encounter against the same opponent, even after a 24-hour interval between fights (Cavallino et al ., 2020). After previous experience against the same opponent, fish resolves subsequent encounters with reduced levels of aggression (number of bites and total time of aggressive behaviors), but this reduction is not observed if the subsequent opponent is different, suggesting a social memory formation (Cavallino et al ., 2020).…”