I'm sorry. I know how you feel. I recently adopted a turtle (red-eared slider) from an oil spill and did everything the best I could. She had the best tank, food, and care. And then one day I found that she had died in a freak accident (drowned after wedging herself under the filter). I was devastated. When I told the rescue what happened they understood how it wasn't my fault and wanted to offer me another turtle. I really did have a nice set-up and they wanted another rescue turtle to enjoy it. But I was so shocked by the whole thing that I don't think I ever want to own another turtle. It was too sad. I donated my stuff to the rescue.

Try not to be too discouraged about the frogs. I think you take great care of them. Check around the tank for anything sharp or rough. You never know what these guys can get into, maybe one of the other frogs bit his foot thinking it was food. If you get him treatment quickly he could be fine! He should probably have some antibiotics and have a vet look at him.

Even the best pet owners have these kinds of issues.