Family Synbranchidae Bonaparte 1835 (Fig. 3K). Swamp Eels; Anguilas de Pantano, Anguilas de Lodo, Anevilas, Anguilas Falsas

Description: Body elongate, eel-shaped, more or less rounded in cross section; up to 100 cm in length; scales absent; eyes small (some species functionally blind with eyes sunken below skin); anterior and posterior nostrils widely separated; pectoral and pelvic fins absent (pectorals present in early development of some species); dorsal and anal fins vestigial (reduced to a rayless ridge); caudal fin usually vestigial to absent (Nelson et al. 2016). Distribution: Tropical and subtropical freshwater, some species occasionally in brackish water (rarely marine); western Africa, Liberia, Asia, Indo-Australian Archipelago and from Mexico to South America (Nelson et al. 2016). Two genera and two species in Nicaraguan freshwaters.