Aside from selling and buying fishes, you can also earn extra coins and experience in many ways. I'll explain them all in this post.
Extra Coins and Experience Through Neighbor Helping
This method works pretty good especially if you have many neighbors. There are ways to help your neighbors, cleaning their tanks and warming or cooling the waters.
Cleaning the stains
Sometimes, your neighbors' or your aquarium get stains and whenever you clean them, you get +5 coins. Usually, each of your neighbors' tanks gets 5-8 stains every 12-24hours. But on your own tank, cleaning each stains gives you +5 coins and +1 exp.
Cooling or Warming the aquarium water
There are also times when the water of your neighbors' tanks needs to be cooled, warmed or adjust the pH levels. You also get random amount of coins and exp for each warming/cooling/adjusting the pH.
Giving Fish Love
Once every 12-24 hours, there will be a heart shaped button at the bottom left side of your aquarium. When you click it, you will gain a random amount of coins.
Daily Bonus
You get extra coins by logging in everyday.
