Common names: blenny (English), cachudito (Espanol)
Lupinoblennius vinctus (Poey, 1867)
Atlantic mangrove blenny
Body and head compressed; a single unbranched cirrus over eye (larger in male), no cirri on nape or over nostrils; front nostril tubular with short filament, rear nostril a raised rim; jaw teeth in single rows, fixed, bluntly pointed, with a canine tooth at rear of top and bottom jaws, canines larger in males; gill membranes free, forming a transverse flap under throat; dorsal fin XII, 13-14, without a notch between spiny and soft parts, soft part of fin higher than spiny part; anal II, 14-16, in males the spines and all but the last 2-3 rays have a swollen fleshy tip; some rays of tail fin branched; lateral line in 2 parts, top part from top corner of operculum to under 9th spine, lower part along midline from above origin of anal fin, short (5-8 pores).
Grey brown; ~ 8 dark-edged square blotches along base of dorsal fin, which tend to connect with dark-edged vertical rectangles on lower body; Y shaped dark bar under eye; male with dark stripe along base of 1st 3 dorsal spines, and a dark stripe near outer margin of membrane between those spines.
Size: reaches 3.7 cm.
Habitat: mangroves and estuaries, entering freshwater.
Depth: 0-5 m.
A widespread Caribbean species; evidently has passed through the Panama Canal and established a population in locks at the Pacific entrance to the canal.