I have small frags of Frogspawn, hammer, torch, blasto, acan(s), and a couple of others. I know these all supposedly have sweeper tentacles that can damage nearby corals, but i have never seen them, even late night when the lights are out at like 2-3am. Is there somthing that triggers them to come out? i have had a candy cane coral 1" downstream(ish) from an acan and they are both doing well for the last month. i'm asking because i have a small 10gal and trying to figure out placement on the corals.