Hitchhiker Crab - Sump him?

[Brit’s Fish]

Found this tiny little guy while dipping a new acro frag just now. Is he a good guy or bad guy? Keeping him in a container for now.
He’s teeny weenie but I can sump him in one of my nanos if he’s a bad guy.

 

[Brit’s Fish]

He kinda looks like this guy?

 

[SaltyT]

The pics are fuzzy but it does look like a commensal crab.