The sand smelt (Atherina presbyter) is a species of marine fish of the family Atherinidae, common in the northeastern Atlantic from the Danish straits, where it is rare, and Scotland to the Canary Islands and the western Mediterranean Sea.

[1] Sand smelt are small, pelagic fishes which are found in coastal areas and in estuaries.

[2] Sand smelt generally live in semi-isolated populations around river estuaries.

[3] The small size of the sand smelt means it often unable to escape being drawn onto screens used to remove fish and weeds from power station cooling water intakes.

In the case of the Southampton Water population it was the species most commonly found on the Fawley Power Station screens.