1. Play match-3 levels. Beating them earns you coins.
2. Feed your fish and your friends’ fish. Happy fish reward you with a few coins.
3. Clean your aquarium regularly. You get a few coins for your hard work.
You can also sell decorations you no longer need.
BEAR IN MIND, however, that your Beauty decreases with each sale, and also that you’ll only be reimbursed half the original price.