I am sorry for the loss of a lovely fish in your tank. I think that there was some difference of circumstance between yours and your LFS tank (?), and it may have found trouble in your home.
In general more than three of flashers, even different spp. can go well together but some may feel fear and hide among rocks, and when it comes out other lively fishes may attack it.
I will search the hidden specimen after introduction when it does not come out all day long for two to three days, but it needs to move some rocks of the tank. If it is fine, with no rapid breathing or injury, etc. I will do not touch it, but when it exhibits coloration of fear with many white dots and lines I may pick it up and house it in another tank or a small separate glass floating in the tank.
I am not sure whether or not it will be all OK after releasing it in two to three days but you may need see it carefully if it takes foods there. If it will be attacked again and again by others it will no longer well in the same tank and should be kept in another different tank.
Good Luck.