Carp? I'm Dragon!

Jack, an ordinary office worker, time-traveled and became a koi fish. He was laughed at by Mermaids. Luckily, Luna saved him and he got a Devour Evolution System. With the system and good luck, he evolved step by step. He turned from a koi fish into a golden flood dragon. He beat those who challenged him and won the Flood Dragon Queen’s approval. Later, he found the Flood Dragon Queen’s evil plan. Finally, he evolved into a powerful sky dragon. He defeated the Flood Dragon Queen, crossed the Dragon Gate and became a real dragon.