Black skirt tetra: Gymnocorymbus ternetzi
Black skirt tetra: Gymnocorymbus ternetzi

The black skirt tetra is also known as black tetra and black widow tetra. This species was introduced in Bangladesh from India and Thailand by the aquarium fish traders of the country (Galib and Mohsin, 2010 and 2011). This fish is native to South America and life span is 3 to 5 years (Fishlore, 2009).

Systematic position
Phylum: Chordata
Class: Actinopterygii (Ray-finned fishes)
Order: Characiformes (Characins)
Family: Characidae (Characins)
Genus: Gymnocorymbus
Species: G. ternetzi

Synonym: Tetragonopterus ternetzi Boulenger, 1895.

Morphology: Small body, almost rounded and highly compressed with large eyes. Posterior part of the body (up to caudal fin base) is black or blackish. Two vertical lines on each size started just after operculum from back to below the lateral line. There are some different color varieties (may be dyed fish, look closely) and even some long fin varieties. They may lose some of the black coloration as they age.  Minute adipose fin and 32 scales on lateral line (Galib and Mohsin, 2011).

SL 61.70% of TL, FL 74.47% of TL, BD 38.30% of TL, HL 18.09% of TL, CP 6.38% of TL and Eye 47.06% of HL (Galib and Mohsin, 2011).

Fin formula: D. 10; P1. 6; P2. 1-2; A. 31; C. 16 (Galib and Mohsin, 2011).

Maximum length: 6 cm (Galib and Mohsin, 2011)

Food and feeding: Occurs in the middle and upper water layers (Galib and Mohsin, 2011). Carnivorous fish. Feeds on worms, small crustaceans and insects (Mills and Vevers, 1989). In aquarium, takes all the aquarium feeds available commercially of suitable size (Galib and Mohsin, 2011).

Breeding and sexing: Egg scatterer. The adults may eat the eggs. The female is larger and male may have a wider anal fin (Galib and Mohsin, 2011).

Behavior: May pose aggressive behavior to some other fishes especially with long anal fin such as angel, glass fish and tiger barb (Galib and Mohsin, 2011).

Economic importance: As aquarium or ornamental fish in Bangladesh and retail price is 40-60 BDT/pair (Galib and Mohsin, 2011). Found in the aquarium shops of the major cities of Bangladesh (Galib and Mohsin, 2011).



Boulenger GA. 1895. Abstract of a report on a large collection of fishes formed by Dr. C. Ternetz in Matto Grosso and Paraguay, with descriptions of new species. Proceedings of the General Meetings for Scientific Business of the Zoological Society of London 1895, pp. 523-529.

Fishlore. 2009. Tropical Fish Information, retrieved on December 12, 2009;

Galib SM and Mohsin ABM. 2010. Exotic Ornamental Fishes of Bangladesh, Bangladesh Journal of Progressive Science and Technology, 8(2): 255-258.

Galib SM and Mohsin ABM. 2011. Cultured and Ornamental Exotic Fishes of Bangladesh Past and Present, LAP-Lambert Academic Publishing, Germany, pp. 85-86.

Mills D and Vevers G. 1989. The Tetra encyclopedia of freshwater tropical aquarium fishes. Tetra Press, New Jersey, 208 pp.


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Black skirt tetra, Gymnocorymbus ternetzi (Boulenger, 1895)

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Shams Galib

Shams works in freshwater ecosystems, primarily on fish diversity in terms of their availability, and richness; he is also interested in aquatic invasive species and their impacts on ecosystem. Email: More...

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