Green Hydnohpora Colony

Definitely a nasty coral if another one comes in contact with it but i have a nice size colony that has been growing for years and I've never seen a sweeper, with corals that thrive within a couple of inches of it.

 

I've had mine for probably about 8 years and I've never seen sweeping tentacles on it.
When I don't prune my pink branching hammer or my pearl bubble corals so they touch the hydnaphora, the hydnaphora dies off where touching occurs but doesn't kill the whole thing.
I've made a lot of money selling pieces off of this coral, just like many other fast growers.
Bottom die off is natural as it continually grows upwards and spreads out as the topmost branches shade out the lower stems. It's how a reef is made I guess.

 

yeah i didnt see a sweeper on the one at the LFS and it was a pretty low flow

 

mine died from STN about 3 weeks after i got it, im not too happy, but hey, what can you do...