Do you have any vet around you? Can you take his poop for fecal exam? You may say it is a tree frog without specifying it is cuban
See the danger of self medicating is that you will try all kind of stuff that wont work, this way you lower frogs immune system, and it can end badly.
You can contact dr. frye, i believe he has no problems with a species.

Runny poop is a sign of protozoa infection, but it could be anything else or protozoa and smth else, so you have to know what are you treating for first.