male and female swimming crab (macropipus holsatus) hiding among algae

macropipus swimming crab animal arthropoda arthropods benthal benthos bentos biological black sea fauna brachyura cancer crabs crawfish crayfish crustacea crustacean crustaceans decapoda ecological ecology europe holsatus invertebrate invertebrates life malacostraca marine nature portunidae reptantia biology seabiological shrimp water waters undersea underwater footage world wild wildlife