Horselover, I just thought of something. You had an ADF in with your frogs earlier on, right? And the AFD died? When, how, and from what did your ADF die?

I woke up this morning and flew to the computer, realizing this- you do know that ACFs are asymptomatic carriers of chytrid, right? Meaning they can have it, and have skin FULL of little fungal zoospores just sloughing right off into the water all the time, and unless you take them to get their tummies skin-swabbed and that sample DNA tested, you will never probably know. They show no symptoms, and are not killed by it. If your ADF died from any chytrid-like symptoms, no matter how slight, I think it would be who of you to get the bullfrogs out of the ACF water before it's too late, and hope it's not already. I just did some looking, and bullfrog tadpoles CAN be infected with and carry chytrid, and, from more digging, they DO die from it. And I don't think we know of an approved treatment for bullfrogs with chytrid.

*This* is another reason why ACFs are best kept in a species-only tank- it's harder to spread diseases when there's no one else in contact with the sick organism. Chytrid wasn't much of an issue with plecos, but adding other amphibians made this a whole 'nother ball game now.