Shorefishes of the Eastern Pacific online information system

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Family: POLYNEMIDAE, Threadfins, Bobos

All Families:   All Genera:   All Species:

head not armoured
pectoral: lower 5-9 rays = long free filaments





Threadfins are small to medium sized fishes (16-46 cm); the body is elongate, compressed; snout short, conical, translucent, overhangs mouth; eyes large, longer than snout, with fatty cover, at front of head; mouth moderate, below, with bottom lip extending to front, but no top lip; tooth bands of top jaw touching in center; preopercle serrated; two well separated dorsal fins, VIII + I, 11-15; anal fin base short, III,10-18; pectoral low on side, divided in two sections, upper section a “normal” fin, 12-19 rays, lower section under gills with 3-16 long free rays, horizontal length of total fin base shorter than upper jaw; pelvics well behind pectoral base, under 1st dorsal; tail forked; scales rough; lateral line extends onto tail fin.

Threadfins are usually encountered near the coast, often in river mouths or brackish mangrove estuaries. Their diet consists of shrimps, crabs, polychaete worms, and other benthic invertebrates. They are considered good eating and are often seen in fish markets throughout the region.

The family is worldwide and contains about 40 species in 8 genera, occurring in all tropical and subtropical seas. Only two endemic species from one genus are found in our area.