I had one casualty from my tank swap...an acro colony that I've had for 3 years. Unfortunately, I had an acro crab that called it home. I attempted to rehome it to another acro colony...he settled in and thought we were good. The next morning he was gone. Two weeks later as the lights came up...found him. Guess he preferred this acro and made quite the journey...around other acros to get to it.