Fiddler crabs are small about 3 inches / 7.6 cm long, distinguished by one large claw, There are over 100 species world wide. The "Atlantic Marsh Fiddler Crab" ( Unc pugnax ) ranges from Maine to Florida.
photo ... duckduckgo.com
video ... at Wading River estuary
Why there are right and left handed crabs
info from .... dec.ny.gov