I responded to your other post but I will post here also - - More information is needed
What are the actual numerical readings for Ammonia, nitrite and nitrate?
20 gallon tank - tall or long?
What else do you have in the tank? Species and number per please
How long has the tank been set up?
Was your tank cycled?
Do you feed anything other than bloodworms? Bloodworms should not be the staple of the frogs diet
How long have you had the frog?
Have you seen it shed recently?
You often won't see it poo - so don't be concerned about that.
Can you describe your tank set up - substrate, decor....pictures of the tank and frog would be immensely helpful.