Yup...looks a lot like the one that lived with my mantis...for a short time.

I've actually had one in my first tank ages ago, and yes they will take out ur fish!! If u can isolate it then do it if not try ur best to get them all out.

If he's small enough...I caught mine with a 2oz glass jigger. I just set the jigger in the sand bed with the lip leaned up against a rock...threw in a small piece of chopped fish. The crab jumped into the glass within 5 minutes!

Once in the glass, they can't climb out.