Hello,

Sounds to me that you just got a lazy frog, I have one that is the same. She will eat but its not as aggressive as it was when she was baby. I have to put it right in front her and she just eats it very calmly, my male ornate on the other hand is lunging at everything. Is it a Cranwelli? They aren't as aggressive eaters as the ornates. I would keep an eye out for any other signs he may ill but all in all I think you just got a frog that's used to his feeding routine and is just a lazy eater.