I did acclimate them before adding to the tank, but it was a short acclimation, probably 15 minutes, because I was at work.
I didn't have very much time to observe the fish. Probably about 2 hours from the time I put him in the tank, until the frog ate the sick one. He was resting in some plants for quite a while, them he swam around a little, then he was lying on the bottom.
I hope is wasn't anything too nasty. It wouldn't be cool if that whole tank of feeder guppies that I got him from was infected with something that could be spread.