Teleostei (teleosts) >
Beloniformes (Needle fishes) >
Belonidae (Needlefishes)
Etymology: Potamorrhaphis: Greek, potamos = river + Greek, rhaphis = needle (Ref. 45335).
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; pelagic; depth range 0 - ? m. Tropical; 23°C - 26°C (Ref. 2059)
South America: Amazon and Orinoco River basins, and the Guianas.
Size / Weight / Age
Maturity: Lm ? range ? - ? cm
Max length : 29.1 cm TL male/unsexed; (Ref. 40653); common length : 12.3 cm OT male/unsexed; (Ref. 10994)
Short description
Identification keys | Morphology | Morphometrics
Forms schools at the surface. Prefers to inhabit marshes, small slow-moving creeks or even in main river beds, in the slowest parts of meandering streams next to banks (Ref. 35237). Voracious carnivore which appears to have a primarily nocturnal habit (Ref. 27188). During reproduction, the male positions itself beside the female or crosswise in front of her. Sometimes the male touches the female with his side, pushing her aside in an oblique position, with their heads oriented downwards. The couple settles next to a bush where the female spawns her eggs (15 to 40). Eggs adhere to plants by means of sticky filaments which are 2 to 3 mm long. At 27-30°C, incubation lasts for 9 to 10 days. Larvae are pelagic and carnivorous (Ref. 35237). Maximum length 40 cm TL in Keith et al., 2000 (Ref. 35237).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
The eggs are attached to underwater vegetation. At 27-30 deg. Celsius the larvae hatch after 9 - 10 days. The larvae are pelagic carnivores.
Collette, B.B., 1982. South American freshwater needlefishes of the genus Potamorrhaphis (Beloniformes: Belonidae). Proc. Biol. Soc. Wash. 95(4):714-747. (Ref. 10994)
IUCN Red List Status (Ref. 130435: Version 2024-1)
Threat to humans
Harmless
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5625 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00126 (0.00057 - 0.00279), b=3.11 (2.93 - 3.29), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Trophic level (Ref.
69278): 3.9 ±0.6 se; based on size and trophs of closest relatives
Resilience (Ref.
120179): High, minimum population doubling time less than 15 months (Preliminary K or Fecundity.).
Fishing Vulnerability (Ref.
59153): Low vulnerability (19 of 100).
