I have been looking into things that aren't clearly outlined in the care guides after the tragic passing of my Pyxie frog last week. Assuming all you parameters are in order for a healthy frog, you should check your water quality. Especially if the frog is trying to digest a large amount of food, it will be dumping lots of nitrates and ammonia into it's water. If they aren't being removed, it may be causing a toxic reaction to your frog.