Silver coins
You will occasionally receive an offer to watch an advertising video to earn money. Always accept it as those offers are infrequent. Sell the fish you catch daily on the home page to earn money and experience points. The larger the fish, the better the reward. Make sure you at least cover the daily fees with the fish you catch in a particular area. Complete the missions and capture the required number of listed fish. If a fish bites, but not needed to complete a mission, release it and keep trying. Completing the achievements usually results in a large silver coin reward. Participate in tournaments after you are skilled and active enough to catch prize fish.