What are we supposed to feed a red-eared slider

I have been reading several websites about RES care and am recieving conflicting information about what to feed them. Some say it is ok to catch wild bugs (worms, crickets) as long as they are not exposed to chemicals, while another says no because of parasites. One site says commercial food should only be 25% of the diet while another says it should be the main staple. One says feeder fish from a pet store are fine on occasion (but never indicates how often) while another says no to certain feeder fish (such as goldfish). One website says 'no' to shrimp while commercial pellets contain shrimp. How much and how often should I feed the turtle? Will feeding him as much as he can eat in 15 minutes (in a separate tub) once a day be too much? I think he is still pretty young..he's about 6" long. I got him from a coworker who got him at a pet store and she was going to release him into the wild. I couldn't let that happen, so I brought him home, but I am unprepared. I have pellots for now.

Obviously there is no hard and fast rule. Keeping pets is more of an art than a science.

I recommend a simple diet: high quality pelleted food. Using high-quality food provides the turtle with the nutrients it needs. As you gain experience, you can supplement it with other things.

Common supplements are live or thawed/frozen fish foods- small fish, worms, bugs, crustaceans, etc.

Shellfish can carry a disease (Sub-Cutaneous Ulcretive Disease, SCUD) that can affect turtles if it gets under the scutes and can colonize there. This is not a big deal if the turtles are otherwise healthy and the cage is clean.