My son and I built an ATBA yesterday and installed it today, which finally let me get some pictures of Toby basking:

However, when I looked at one of those basking pictures, I realized what I had suspected from looking at him in the water. I'm pretty sure we're overfeeding him.
Click for higher resolution picture:

I've not measured Toby, but those small rectangular blocks are 0.5 inches and the larger square ones are 1.25. I'm estimating him between 1.5 and 1.75 inches.
Toby is a wild caught turtle. I realize that may be a controversial admission, but I wanted to give full details. The family was in the car one Sunday and my 12 year old son was begging for a pet, a pretty common occurrence. As he was running through possibilities and having my wife say, "no," he said turtle and my wife said sure, he could have one.
That Monday he was begging for me to go to the pet store to get him one and I said we could wait until the weekend.
That Tuesday (July 17), when I got home, there was a tupperware bin next to the kitchen sink with a 6+ inch Eastern Painted Turtle and a baby RES in it. His friend and he had gone to a nearby pond and gotten some turtles. We released the larger turtle and headed to a pet store for an aquarium and supplies. I got bad advice and was pointed towards a 20 gallon kit with a reptile waterfall filter that was wholly inadequate for even a turtle of Toby's size.
After setting it up, some online research led to me here and that I should have gotten a much larger tank. That also led to the purchase of heat lamps and UVB lights.
I'm committed to providing a good home and have been checking Craigslist for larger tanks, as well as dropping by the area pet stores to see what they offer.
I don't have pictures of Toby when we first got him. We initially started with Reptomin baby pellets. We started with 4, based on our guess at what would fill his head. He ate nothing for the first few days, but quickly started begging whenever we came by the tank. Soon after he was eating the Reptomin, we started putting lettuce (romaine and red leaf) in the tank, which he will eat. Within a week or so, we upped it to 5 Reptomin baby pellets.
At some point, we also picked up Omega 1 Juvenile Pellets and have been offering both. We've been feeding a total volume that is about 5 Reptomin baby pellets in size, while also keeping fresh lettuce available at any time.
Here's a picture ten days after we got Toby. He is probably already showing signs of being overfed, but I didn't recognize it. It's quite a bit different from the picture above which is 17 days after this one. That is, the picture above is 27 days after my son caught him and the one below is 10 days after. Again, click for a higher resolution:

So, my question is how I deal with this? I've been spending a lot of time going over old threads here. Tough love seems to be recommended for older turtles. My plan is to cut back to the equivalent of 3 Reptomin baby pellets for a bit and then after a week or so, go to 4. I'm thinking to always keep lettuce available.
Another thought is cuttlebone. When we first got him, I put some cuttlebone in, which he ignored. However, today a few hours before the regular feeding time, I put in a small piece of cuttlebone, and Toby did eat some. My thought is that it has little nutritional value to make him grow, but will help to fill him up.
I'd appreciate any thoughts or suggestions from others here. I'm already incredibly grateful for this forum and can't express my appreciation of the many posters who have offered help here. I may not have asked that many questions in the first month of having Toby, but I have gained lots of useful information from all of you. Thanks.

