Can you post any pics?
b.g. I'm so so very sorry your little frog is sick. I have 2 ADFs that I just adore. They are so cute and funny. I'm pulling for you and your little frog.
Mo, those are great links. I'm bookmarking those links.
b.g. I hope your frog will be ok., You could try the antibiotic treatment for your frog.
Just in case you need to euthanise, here is some information.
This article dealt with a problem with a particular frog species that is invasive, but the euthanasia method would be the same for any frog. I hope it doesn't have to come to that for you, but just in case. Here it is.
A humane method for euthanizing amphibians:
To euthanize a Cuban Treefrog, hold the frog firmly in your hand and apply a 1 inch bead of benzocaine ointment along the back of the frog. Benzocaine ointment is a topical anesthetic (a numbing agent) used to treat skin pain (e.g., from sunburn) and itching as well as toothaches and sore throats. There are a variety of name brand and generic versions that are available over-the-counter in a tube or spray. If you are able to, using a gloved finger spread the ointment out on the frog's back. Alternatively, you could use a benzocaine spray. Once the ointment or spray is applied, place the frog in a plastic grocery bag or a sealable sandwich bag for 15-20 minutes so that the benzocaine has a chance to render the frog unconscious (be sure to seal the bag or tie it closed). After the bezocaine has anesthetized the frog, place the bag in a freezer overnight to ensure that the frog is dead and then throw it out in your trash. If you are unable to apply benzocaine to the frog, you can simply put it in a plastic bag, seal or tie the bag shut, then place it in the freezer overnight--dispose of the bag and the frog in the trash the next day. Do not throw a bagged frog into the trash without euthanizing it first. Remember, Cuban Treefrogs have a noxious skin secretion so be sure to wash your hands thoroughly after you handle the frog, even if you wear gloves or use a plastic bag.
Freezing is a humane way to kill amphibians because their bodies go into a state of torpor (metabolism slows way down) -- just as they do in cold weather outside. If the cold weather is short in duration, the frogs will come out of their torpor state. However, after an extended time in freezing temperatures, the frogs die.
A good test to determine if a frog is a Cuban treefrog is to grasp the frog firmly, but gently, and try to move the skin around on the top of the frog's head with your fingertip. The skin on the head of a Cuban treefrog is fused to the top of the skull and won't move.
Be sure to wash your hands after handling any frog or toad. They all secrete a slimy film to protect their skin, but the secretions of some species, like the Cuban treefrog, can irritate the skin and eyes of some people.
I'm sorry we couldn't help in some way. I know you'll keep a careful eye on your other two. 