Fish have different personalities which change as they experience life's highs and lows.according to British biologists. Researchers identified different"personalities" in their fish by observing the boldness or shyness of individuals,according to The Nature.Like people,some fish are very confident in the face of novelty or conflict;while others are silent and fear. The scientists selected particularly bold and shy rainbow trout,and tested whether they changed their outlook depending on what life threw at them.They arranged some fish to fight and others to  watch to  see how both the participants  and  observers  responded to victories  and defeats.Winning or losing a fight,or even watching fellow fish overcome the difficulties influenced the future behavior of the _ studied in the lab. The researchers made fish compete with much larger or smaller opponents.to ensure that they would win or lose their fights.These bold fish that won their fights tended to be even bolder when later presented with  a novel food  item;losing their fight caused them to be  much more cautious. Fish also learn by watching others.Bold fish watching a shy fish exploring a mystery object were much more nervous when later given a novelty item for themselves. Predictably,shy fish that won a fight also gained more confidence,but surprisingly,shy fish that lost their fights also grew bolder when exploring strange new food,Sneddon said,adding that this could be due to what she calls a"desperado effect" . The new research suggests that animals can gradually adapt their personalities.The results echo the effects that life experience can have on human. What's the main idea of the text?'
Fish have stress in the fierce fights. Fish care about winning or losing a fight. Fish have adaptable personalities. Fish can learn a lot by watching others.