How do you level up quickly in tap fish

1. Get about 1000+ coins.
2. Buy a new tank.
3. Put 50 fish on the new tank. Be sure to feed them.(+50 exp)
4. When they are adult, sell all of them. (+100 exp)
5. Rinse and Repeat :D
You also get money this way. I recommend using fish that grow up in one day so you get 150(for every tank) exp per day. Once you get enough money, you can get more tanks to get more exp per day.