Green Algae spots will appear often in your tanks.
It is important to keep your tanks clean to keep your fish happy and alive. Your fish will be unhappy and you may get Sick Fish if you don’t clean it.
You will earn +3 coins when you have cleared the algae from the tank.
Simple… just click on the green spots and they disappear! As soon as you open a tank that is dirty, you will have a sponge “in your hand”. Just click 3 times anywhere inside the tank to clean it. Be sure to click slowly though, because clicking too fast will make the sponge get stuck on the cursor. If that happens you can try to navigate to a different tank or just refresh your game by hitting “Play”.
This tank is dirty, as noted by the Cleanliness bar being red.
Make sure you clean your tanks before selling your fish so you don’t lose any coins when you sell them.