The inland silversides, Menidia beryllina, of the family Atherina, was introduced from the mid-western U.S. into Clear Lake, California, in the hopes that it would control the aquatic larvae of the Clear Lake gnat, Chaborus astictopus. Although larval gnat populations declined, nearly simultaneous applications of pesticides to the lake made it difficult to determine the efficacy of the fish for controlling the gnat.