Chyrid fungus as Jessica mentioned is a good possibility. The fungus attacks the frogs skin and causes the skin muscles to tighten and no longer allows the frog to obsorb water through its skin. This causes dehydration and death. As it also attacks the frog when it is weak once the actual signs show up it is nearly too late. The way he was trying to get water makes me suspect that it could have very well been chytrid that may have played a serious role in Manderin's passing. Again I am sorry. Jessica is right though. Your frog would have to be tested for the fungus. I hope you meet with more success this next time around.