This happened to one of my treefrogs awhile back. If you haven't already use dechlorinated water and pretty much do what Mentat said in his previous post. All I know is that my treefrog that had symptoms like this a long time ago died from it. Could be ranavirus, I would also search it up on google if you haven't already and read up on that disease. Here are some websites on ranavirus Froglife, USGS National Wildlife Health Center - Ranavirus. I would also clean out the aquarium that the frog is in really well without using any chemicals and soap. Does the frog show any other odd behavior?