Personality plasticity in trout

Does experience influence the personality of fish? A paper by Frost et al. (2007, Proc R Soc B, 274, 333-9) found that 'bold' rainbow trout who lost fights or who observed other trout exhibiting 'shy' behaviour became less bold themselves. This was tested behaviourally by examining fishes' inquisitive reactions to Lego bricks or novel prey dropped in front of them. However, there was an asymmetry to this social learning: shy trout who observed bold trout did not subsequently become bolder. Fish who won fights tended to engage in more approach behaviour towards novel objects, although this was also true for shy fish who lost fights (the so-called 'Desperado' effect).