Birds nest problem
 

My new birds nest(tan colored)has one of the small arms starting to bleach and shrink.I have it under 250w mh with actinic near the surface with moderate flow,all levels seem fine.The rest of the nest is looking real healthy,just the one tip,so should I cut that part off to save from spreading or just leave it?The other corals such as the gsp,hammer,candycane,green tree leather,shrooms,and several diff colored zoos are doing real well(seeing new growth daily)

Jim

I'd leave it and see if it stops on it's own.

Something could of stung it, maybe an LPS sweeper. It will recover if so.

I would be careful with a frag of that size. I almost lost my entire colony due to tissue loss. Watch it carefully and be ready to remove the damaged part if it gets close to an intersection of the branches.