It looks like a grouper?

[LeslieH]

Yes, the dive was during the day. Follow up question, I have photographed other basket stars in branching corals (as shown in the thumbnail). I notice that the color and locations seem very different (in the branches vs in a crevice). Are these two different types (species) or does it just represent the variety among the same species? (I am using "species" as the lay-term not the technical...)

It does look like a different species. There are a number of them in the area. Astrophyton is just the most conspicuous because of it's size.