Goldfish pellets are a good choice since they are more nutrient rich than flakes and are easier for the fish to keep track of. You can also provide them with brine shrimp. It is wise to give them several small meals daily, just enough to consume in a few minutes. Make sure you remove any food they have not eaten.
Cleaning the Tank
The tank should be cleaned once per week. Rinse all items throughly with warm water. Never use soap on anything that will come in contact with the fish.
When changing the water, refill the tank with about 25% of the original water, and 75% of fresh water. Tap water or distilled water can be used in the tank. Check with your local pet store to determine if you must treat your tap water with an additive to make it safe for the fish.