I'm NOT saying don't take your turtles to the vet, but I do wonder about the benefits of vet care...sometimes! Turtles don't normally get treatment for their ailments, and the stress of going to the vet and us putting meds on them etc. might make it more difficult to naturally fight off ailments.

Try raising the water temp a bit. Get a UVA/B bulb. Make sure it is both A and B. Get it as close to the basking spot as possible w/o danger of the turt burning itself. I can't say enough about the huge changes in all my turts since I started using UVA/B bulbs at close range like this!

Is the turt still active and eating well?
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0.1.0 ornate box turtle
1.0.0 eastern box turtle
1.0.0 Yellow belly slider
0.1.0 Red belly cooter
0.1.0 Australian shepard
1.11.0 chickens
1.0.0 Dutch(rabbit)
3.2.0 children (do I still count the married ones?)
1.0.0 husband