As I sad, I never had a sick clawed frog before and I´ve been keeping them for about 5 years or so. They realy like big earthworms, I once had a clawed frog and she ate 5 worms that where 25 cm each in 1 time. I also gave her a big mouse: My african clawed frog eating a mouse part 1 - YouTube
I wonder if she was a real Xenopus laevis or not some other species, both male and female where very big, the female was about 30cm when she stretched her leggs.
I also had a male at that time and he was about 15 years old or so was only being fed earhtworms.