OK, first thing need to do is please answer these questions and provide requested pics:

1. Size of enclosure?

2. # of inhabitants - specifically other frogs and size differences?

3. Humidity?

4. Temperature?

5. Water - type - for both misting and soaking dish?

6. Materials used for substrate?

7. Enclosure set up i.e. plants (live or artificial), wood, bark and other materials. - How were things prepared prior to being put into the viv?

8. Main food source?

9. Vitamins and calcium? (how often?)

10. Lighting?

11. What is being used to maintain the temperature of the enclosure?

12. When is the last time he/she ate?

13. Have you found poop lately?

14. A pic would be helpful including frog and enclosure (any including cell phone pic is fine)

15. How old is the frog?

16. How long have you owned him/her?

17. Is the frog wild caught or captive bred?

18. Frog food- how often and if it is diverse, what other feeders are used as treats?

19. How often the frog is handled?

20. Is the enclosure kept in a high or low traffic area?

21. Describe enclosure maintenance (water changes, cleaning, etc)

If frog was fed live fish for 4 years it might not associate pellets or worms with food. Keep offering small amounts in morning and evenings but remove all non eaten food in 15 minutes. Could also try a product like this: JurassiPet. JurassiGuard to enhance flavor or just rub pellets in crushed garlic.

More information to read here: Xenopus laevis care sheet; All About African Clawed Frogs; and In Depth Information on Common Aquatic Clawed Frogs. Good luck !