Wow so many emeralds and they didn't even dent it? Now i guess i should ask are you sure they WERE emeralds? The way to tell supposedly is by a red dot on the inside fold of thier big claw. Look at the first joint.... I dunno. Also they should have ,looking from the top, thin flat claws as opposed to pointy ones.
I've heard the foxface fish eats it readily. They would fit fine in your 90 if you can fit another fish.
Just remember if you decide to get one that they are top spine venomous and need to be handled with care. They also full size reach about 8 or 9 inches. I think they are a very cool looking fish because they can color morph and are pretty to begin with. Nice bright yellow with a black face is the common one. But some rabbitfish(foxface family) have some greenish/teal stripes if remember correctly and all can change color. Oh and also remember they spook easily, i.e. they will jump out, so until they get used to your tank minimize activity in it
