crab in eye of chalice

[Spyd]

Chalices are extremely finnicky. They require acclimating to your lighting. When you purchase one, you need to acclimate them with low light, then slowly get them used to your ideal lighting. Put them in a shady area at first. The crab is probably just feeding off of it if it is dying away... Do you feed your chalices? Target feeding once a week or more is usually needed as well.

The other corals are probably getting blasted with too much light right now as well. They need to be acclimated to a change in light. If you went from a low par light to a high par light fixture, it will be too much for them. If it is dimmable, dial it down a lot to start, then slowly increase it over a month or 2 until you are satisfied with the amount of light. If it is not dimmable, then I would consider using something like eggcrate over the tank to cut down on the light intensity.