Crab id from description

[barnabus's gimp]

after looking a bit more it is definitely a xanthid crab, if is it just a FOWRL tank this is a beneficial inhabitant, if this will be a reef tank you should probably drop it in a sump where it will thrive with no intervention.

 

[Mustang Boy]

this will be mostly a FOWLR but it is going to have macro and a few leathers and some zoas so i will find something to do with this guy. for now i have captured him and he is residing in a betta bowl in the tank so he cant go off hiding where i cant get him again. now i dont have a sump because this is not a drilled tank and i have nowhere to mount a sump so i am just going to keep him in his little betta bowl for now until i find a place to put my 6g eclipse then i will put him in there to live until i get a mantis for that tank then he will become dinner.