Pom pom crabs aggressive?

[GreenSpottedPuffer]

Well unfortunately the jawfish is looking pretty terrible tonight

The "sting" marks are quite irritated looking and he is gasping. He won't eat anymore either.

I don't know what else in the tank could possibly sting him.

Just seems too weird--find the jaw out of his cave (never comes out) with sting marks on his body, curled up in the corner of the tank, then find the crab in his cave, waving its anemones around...