I can't kill mine (with out really trying) if they are dropping branches keep a close watch or they will be all over your tank before you know it. I have found that if I let my tree coral get used to to the high flow it dose just fine (getting blasted) but it will take about 1-2 weeks for it to get used to the flow and it will stay "stocker". Oh ya the worse my tank gets the better thy do too so if I keep my water good they grow slower (just an observation not saying you want bad water). How long have you had it for?