turtle size

Question
I have a western paint around at least 6 mos old with other hatchlings.  He is fed separately along with his tank mates of whom each is the same age.  Each turtle is separated during feeding.  They eat canned snails, pellets, shrimp, and mealworms.  He eats like a horse and is visibly healthy but has not visibly grown at all unlike his tankmates.  They have doubled in size.  His plastron is flat and healthy.  Should I be worried?  Thanks, Wayne

Answer
Hello. As long as youre providing all the needs then I wouldnt be to concerned. You make no mention about husbandry such as UVB lighting, temps etc which makes it a little harder to reply however, assuming that you are providing the proper care then he should grow as HE feels meaning he will grow to his ability.  What size enclosure are they in?
If you send me more info I will help.
I need:

care  lights, heat temps
size of enclosure
is he being dominated
feeding schedule
are you offering calcium

please let me know so i can help