Gregarious, can sometimes be aggressive or calm. Frequents slow-flowing waters of creeks and swamps (Ref. 27188). Lives in groups at the surface. It is capable of capturing small aerial insects. The females are bigger than the males. Feeds on worms, crustaceans and insects (Ref. 7020). Has not been bred in captivity (Ref. 27188). Aquarium specimens reach 6.5 cm TL (Ref. 7020). Aquarium keeping: in groups of 5 or more individuals; may jump out of the aquarium; minimum aquarium size 80 cm (Ref. 51539).

Gasteropelecus sternicla is known to naturally occur in the Amazon river basin and most of its tributaries. Most of the scientific expeditions that have collected this particular species have done so in the far north of the Amazon river system (Hems 1983).

Distribution map of the range of G. sternicla from the   NEODAT II Project.

Biogeographic Regions: neotropical (Native )

South America: Peruvian Amazon, middle Amazon, the Guianas and Venezuela (Ref. 39056). Recorded from the Paraguay basin (Ref. 81048).

Female Gasteropelecus sternicla are known to reach a maximum length of about 49 millimeters (mm), while their male counterparts reach a maximum of about 42 mm. They have a compressed body with near circular pectoral and abdominal regions. This area of the its body contains a group of well-developed pectoral muscles that may make up 25% of the its body weight. The pectoral fins are upward-facing and wing-like. The dorsal fin is placed in a small dip in an otherwise straightened back near the caudal peduncle. The caudal fin is rather unremarkable in appearence and of normal size. The ventral fins are smaller than normal and rather insignificant. The anal fin has a long base and ends near the tail base (Hems 1983; Davenport 1994; Alkins-Koo 2000).

3.8 cm SL (male/unsexed; (Ref. 39056))

As stated earlier, G. sternicla lives in the Amazon river and most of its tributaries. Here the fish lives near the surface. It frequents well-vegetated areas near shore, but when schooled, will venture out into open water (Hems 1983).

Terrestrial Biomes: rainforest

Aquatic Biomes: rivers and streams

pelagic; freshwater; pH range: 6.0 - 7.0; dH range: 15

The hatchet fish has a diet which is composed primarilly of insects and larvae. They only feed near the surface of the water, so many terrestrial insects which they eat have fallen into the water. A large part of their diet consists of many winged insects, a large assortment of aquatic insects, and some zooplankton such as daphnia (Hems 1983).

Research has shown that Gasteropelecus sternicla only breed for a short period coinciding with the start of the rainy season. The eggs are laid by the female, then the male will swim near the eggs and release his sperm. It is not known if the female releases all of her eggs at once, or if they are deposited at different times during the breeding season. It is known however, that all of the eggs are developed at the same time in the ovaries. The unusal shape and body cavity size of the species may account for the fact that its brood size is generally smaller than other tropical fishes of its size. Females as small as 33mm, and males as small as 31 mm, were both found to have mature gonads (Alkins-Koo 2000).

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 10
Species With Barcodes: 1

US Federal List: no special status

CITES: no special status

Not Evaluated

No adverse relationships with humans known.

This species is a popular aquarium fish. It has been in Europe since 1912, and in America since at least the 1930's (Hems 1983).

aquaculture: commercial; aquarium: commercial