I purchased 2 Yuma colonies from my LFS recently, each containing about 10 individuals. Got them home and aclimated them at the same time, introduced them to my DT at the same time and positioned them right next to each other in my DT. The next day, one colony was open and looking incredible, and the other was shrivled and some appeared to be releasing themselves from the rock. They never got that far though, all the Yumas in that one colony melted except for one. The other rock is fine. I have no way to explain why or how this happened but I've been keeping Yuma for several years and its a problem that I've always had to deal with. Hit or Miss.