I finaly got to bring home the bimac last night. It didn't want to leave the bag at first, but after some coaxing it went into the tank just fine. It's got about a 2" arm span, and was chasing pods around the rock after 15 minutes. Funny part was, it didn't seem to like the sand sticking to it's arms. So it would be chasing a "bug" around the rocks, follow it into the sand, and immediatly "jump back" and find another pod to chase.