couple o' questions & in need of tips

I would move the Hydnophora down in the tank.

Let it acclimate to the lighting.

First I would frag it though. Get rid of all the dead skeleton, just a place for algae to grow.
Judging by the images you have some good sized tips left.

Hydnophora is light loving but it can take lower levels of light as well. Mine sits at the bottom in a shaded area. I would just acclimate it to the lighting slower. A hardy coral, extremely aggressive towards other corals. Very long stinging sweeper tentacles.

If you can keep the Acropora alive the Hydnophora should perk up with time.

 

Sorry about the crab they can be killers of coral's , i truly was hoping for a reef safe one. In that sence it's a 50/50 shot on whats safe...

BEst chance is to move or relocate it..


Happy reefing.!