1. Change the water once a week. Don't change the water too often. It is suggested to keep some aquatic plants in the fish tank. 3. Adjust the water temperature to 18~26 degrees. 4. Sprinkling some salt every time you change water can prevent diseases. 5. Keep the fish semi-hungry, so the fish will be more active. 6. If you use tap water when changing water, you should expose the water for three days. 7. Get proper sun exposure. 8. The water temperature should be constant.