蛟龙得水（蛟龍得水）　

◎ 蛟龙得水 jiāolóng-déshuǐ

[to have an opportunity to bring one‘s ability into full play] 蛟龙欣逢雨水。喻指君主得民心;英雄逢时大有凭藉、施展之机

所谓蛟龙得水之秋,自此一举,此后不复与诸君伍矣。——《北史》