Sand gobies are small gobies (up to ten centimeters). They can grow up to 10 centimeters in length. They have a suction cup on their belly to attach themselves to stones on the sea bottom. Sand gobies usually lay their eggs in empty shells, which the male guards until they hatch. These gobies eat copepods, gammarids, chameleon shrimp and fish larvae. Sand gobies themselves form an important source of food for large fish such as cod. These predators approach the coast at night to hunt their prey.