Heart crabs are a reef predator. They eat worms, screwcap shells, and even reefbuilder crabs and are only repelled when attacked by superior numbers. That this often happens has caused some to band together for protection and to provide distractions so others can steal food from the reefbuilders. Heart crabs are heart-shaped and have two heads. They crack open the shells by smashing them against other shells.
Written by Daniel Noe, Champion Of The Galaxy