Now he's dead, which is heartbreaking, because I held him in my hand under the water for a good half hour while trying to feed him, and when I did force feed him, I did so very successfully. He cooperated in the end, and I was very gentle. The air bubble had gone down, which might mean he was getting better when he died or that the air escaped when he died. I don't know. I just know I am very sad about it now. I did everything I was advised to do to no avail. I'm sure someone here will say the organic plain yogurt I fed him did him in. That's fine. I did what was recommended to me by the only vocal professional at the time, and that's how it goes I guess. I'll continue to treat my tank for the next week to prevent the other life in the tank. I will get rid of my pleco, and get another frog to keep Arthur company. Farewell Ford.