Common names: goby (English), gobio (Espanol)
Microgobius crocatus Birdsong, 1968
Head and body compressed; low fleshy crest on nape only in female; 2-3 pores on preopercle; mouth large, nearly vertical; tip of tongue divided; dorsal fin VII (in both sexes 3rd to 5th dorsal spines very long, extending to end of soft dorsal) + I, 17-18 rays; anal I, 17-18 rays; pectoral fin relatively long (25% of SL), 21-24 rays; tail fin long, oval or pointed (in males); pelvics fused to form disc; patch of rough scales on flank behind base of pectoral fin, remaining scales smooth, scales on body from pectoral axil rearwards - in 46-56 lateral rows.
Both sexes: caramel brown; a blue stripe under eye and several blue spots on cheek and operculum; pectoral base with blue and yellow spot; flank with a blue stripe joining a large blue blotch on side above anus; a blue blotch on chest; lips and outer part of pelvics yellow: tail fin with 3 central red streaks at its base and a yellow lower margin. Male: pale spots on first dorsal, a red line along rear base of second dorsal; anal fin dusky with yellow outer margin. Female: anal fin dusky, with a yellow stripe along its base.
Size: 4.6 cm.
Habitat: mangroves with mud bottom.
Depth: 0-6 m.
El Salvador to Ecuador.