Strongylura fluviatilis

Common Name

Freshwater Needlefish

Year Described

Regan, 1903


Dorsal Fin: 15-16
Anal Fin: 16-18
Pectoral Fin: 10-12
Pelvic Fin: 6

Very elongate and rounded in cross-section. Jaws long and thin. Dorsal and anal fins with raised anterior lobes. Caudal fin with a slightly enlarged lower lobe. Caudal peduncle with no keel. Scales small (180-200 in predorsal series).


Body pale with a olive sheen on the back. A silvery lateral stripe is present. A small dark blotch above pectoral fin base is diagnostic.


Maximum size to 45cm SL.


Freshwater rivers. On the Pacific drainage occurs in estuarine and mangrove areas, but not found in brackish water on the Atlantic drainage.


Rio Atrato drainage, Colombia. Also the Pacific drainages of the western Andes.


Banford, H.M. , E. Bermingham & B.B. Collette. 2004. Molecular phylogenetics and biogeography of transisthmian and amphi-Atlantic needlefishes (Belonidae: Strongylura and Tylosurus): perspectives on New World marine speciation. Molecular Phylogenetics and Evolution v. 31: 833-851.

Lovejoy, N.R. & B.B. Collette. 2001. Phylogenetic relationships of New World needlefishes (Teleostei: Belonidae) and the biogeography of transitions between marine and freshwater habitats. Copeia 2001 (no. 2): 324-338.

Other Notes

A freshwater species included because of it’s close relationship to other New World Strongylura. This species is closer to the East Pacific S. scapularis than any Atlantic species and the ancestral populations of this species were likely isolated in the Atlantic Rio Atrato drainage by tectonic upheavals (Lovejoy & Collette, 2001, Banford et al., 2004).