The minnow-like fish swarming in tidal creeks at low tide, or in the marsh at high tide, are mummichogs, the most common of the species of killifish that thrive in Georgia estuaries. Killifish are found in fresh and brackish habitats in much of the world; some brightly colored species are popular as aquarium fish. The name 'killifish' most likely derives from the Dutch word 'kill' used in New England to refer to a creek, river or arm of the sea. Mummichogs are small, broad-headed killifish abundant in salt marsh estuaries along the US Atlantic Coast. 'Mummichog' originated from a term used by the Narragansett tribe of Native Americans to mean 'going about in crowds', which aptly describes the schooling behavior of these little fish as they hunt bristle worms, grass shrimp and insects among the cordgrass stalks. Mummichogs are, in turn, an important source of food for larger fish and wading birds.
Photo of a mummichog, from Wikipedia Commons. Taken at St. Michaels, Chessapeake Bay in 2006 by Brian Gratwicke. Used with permission.