Figure 1.

Experimental procedure to assess the presence of winner/loser effects in tilapia. (a) Four fish matched for size are placed in individual compartments separated by removable opaque partitions (social isolation); (b) after a period of social isolation, the central divider is removed and a fight between the two fish placed in the central compartments—the focal fish—is promoted (first interaction); (c) after assessing the winner and loser, the divider is put back in place and the winner and the loser of this first fight are back in their initial compartments (interval between the first and second interactions); (d) 2 hours after the end of the first fight, the lateral dividers are removed and two simultaneous fights are promoted between the winner of the previous fight and a neutral male and between the loser of the previous fight and another neutral male (second interactions).