Family Atherinopsidae Fitzinger 1873 (Fig. 4E). New World Silversides, American Silversides; Pejerreyes Americanos

Description: Body elongate; up to 100 cm in length, but usually less than 20 cm; mouth anterior, opening at the front; upper jaw extendible; small teeth present on both jaws and sometimes on the front of the roof of the mouth; eyes large; lateral line absent; pectoral fin inserted high on body, above the mid-level of the eye; pelvic fin on belly, with one spine and five rays; two well-separated dorsal fins, the first one with 2–9 spines, the second one with one anterior spine; anal fin with one anterior spine; caudal fin forked; body often translucent, with a silvery lateral stripe (Robertson & Allen 2015, Nelson et al. 2016). Distribution: Marine (pelagic coastal) brackish and freshwater; temperate to tropical North, Central and South America (Nelson et al. 2016). One genus and six species in Nicaraguan freshwaters.