This seems most closely related to the symptoms of your frogs behavior right now:

Acts spasmodic, is active but loses weight, dry skin.
Worms.
Treat with ERGAMISOL(LEVAMISOLE) 1 drop in 3 drops of tepid water, pour water over frog's back, then place and leave one drop on its back. Duration: 7 days.

I would wait a few more days before diagnosing him with possibility of having worms. Just keep his substrate moist, keep changing the water like you're doing (de-chlorinated), and keep the temperature and humidity up to where it's supposed to be. Temperature 80-85F Daytime (Few drop in degrees at night), Humidity 70-80%. Let him acclimate in his new environment, it's most likely moving stress that has caused him to not be interested in food as of now.

Here's the Basic Frog First Aid as a reference if you want to look it over to get a good understanding of all the common illnesses of a frog and how to treat:

Frog Forum - Basic Frog First Aid

Hope you get him to eat soon. Good luck.