The Atlantic thread herring (Opisthonema oglinum) is a herring-like fish in the family Clupeidae.

It has a dark blue-gray back, silvery sides, a white belly, and a small head.

It can be found in shallow waters and harbors along the coasts of the western Atlantic Ocean, from Cape Cod south to Brazil, including the Gulf of Mexico.

It feeds mainly on plankton, but also takes small fish and crustaceans.

It is confused with the scaled sardine, Harengula jaguana, by anglers.