Crab isn`t bad, if you feed it... Just feed little bit extra next to his cave and everything will be ok.. I have 7 crabs in my aquarium, no problem what so ever... They are cool, and when they grow up, you can eat them.. omnomnomnom
[ame=http://www.youtube.com/watch?v=7IlKwcAmrHM]Sand,gorilla crab and blue cheek goby - YouTube[/ame]