well, I didn't get any replies so I took the initiative to call my vet and he didn't say anything about it being harmful to my frogs. He did say that 1. If they are eating the gnats/gnat larvae then it lowers my feeding costs, because they they wouldn't be eating much, and 2. to just clean everything out and I can cover the tank with mesh cloth to keep the little gnats out. That was about it from the doc, so I'm not going to worry too much about the gnats, but I'm still going to try and keep them out. when I took a piece of decor out, I think it had about 50-75 worms on it, gross!!

I suppose if your ants aren't attacking your frogs you should be OK? I might call a trusted vet if you have one.