I got the crabs

[Jgeebs413]

So these came with my tank there's 3 all together only 2 pictures living happily in my sump. Shown pictures to Lfs and no ones Id'd them. Worth keeping around? First one is small about an inch or so from side to side of she'll. Second one is about 3 or 4 measured same.

 

[Maritimer]

These look like Western Pacific Grapsid Crabs, also called Asian Shore Crabs. Native to Eastern Asia, they're a common invasive species along the East Coast of the U.S. Keep them in your sump if you like 'em, but they're moderately aggressive, carnivorous and quick - not likely a good reef resident.

~Bruce

 

[Jgeebs413]

I figured as much and I know they're really fast. Had the small one in my DT but moved it when I got fish.

 

[Palyzoa]

Cool looking crabs!

 

[Jgeebs413]

They're pretty cool except for jumping the sump into the return side and tore a scallop open so I've learned to feed them extra.