Carp fish, dragon's gate:
The proverb "carp fish leaping over the dragon's gate" li3 yu2 tiao4 long2 men.
The meaning of this proverb, simply is, if a person works hard at whatever he does, he could one day become successful. This proverb is used to encourage a person to persist in one’s endeavor.
In the past, a carp leaping over the dragon’s gate was used as a metaphor for success in passing the imperial exams.