One of you knows what is good to eat. I'm betting that it is your turtle. Juveniles are carnivorous. However, I wouldn't use ground beef; it's awfully fatty, as are goldfish. Other live fish are good, as are earthworms, soft-bodied insects, and strips of liver or lean meat, preferably dusted with bone meal. Once the turtle reaches maturity, you can start adding dark green leafy vegetables to its diet.