Animal Diversity Web

Geographic Range

Osteoglossum bicirrhosum are native to the Amazon drainage system, the western Orinoco and the Rupununi and Essequibo systems of the Guianas. When found in other locations it is because of introduction by man. For example, they have been introduced in secluded areas of California and Nevada. It is also thought that the fish have not distributed themselves further up river because they cannot pass through rapids successfully. (Goulding, 1980; Nico, July 18, 2000)

• Biogeographic Regions
• neotropical
  • native

Habitat

Osteoglossum bicirrhosum live in both the white and black water floodplains of the Amazon as documented in a recent study of the fish communities. In both types of water they were most abundant in the flooded/swamp areas. Osteoglossum bicirrhosum are usually found in the shallower of these waters because of their predatory behavior. (Goulding, 1980; Saint-Paul, et al., March 2000)

• Habitat Regions
• tropical
• freshwater

• Aquatic Biomes
• rivers and streams

Physical Description

Osteoglossum bicirrhosum are characterized by remarkable scale arrangements in which the scales are large, stout, bony and ornamented in a way that the radii form a course pattern. The scales are a pearly silver in color and change to reds, blues and greens as the fish ages. They are also well known for their bony tongue, after which it is named. Osteoglossum bicirrhosum are laterally compressed with a huge oblique mouth. Many oral bones bear teeth, including the jaw, palate, tongue and pharynx. They reach a maximum length of about 120 cm. (Goulding, 1980; Nico, July 18, 2000)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Average mass

  4600 g

  162.11 oz

• Average mass

  2530 g

  89.16 oz

  AnAge

• Range length

  120 (high) cm

  47.24 (high) in

Reproduction

Osteoglossum bicirrhosum spawn at the beginning of the floods, December and January. The females produce a rather small number of large eggs. The males carry the eggs, larvae and early juveniles in their mouths until the yolk sac has been absorbed, which is about 2 months. (Froese, March 7, 2000; Goulding, 1980)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • external
• oviparous

• Breeding interval

  These fish breed once a year.

• Breeding season

  Osteoglossum bicirrhosum spawn at the beginning of the floods, December and January

Lifespan/Longevity

• Average lifespan
  Status: captivity

  6.5 years

  AnAge

Behavior

Osteoglossum bicirrhosum have a unique predatory behavior. They stay close to shore and wait for prey to swim by. They usually keep lateral with a downed tree, to hide. Then they attack their prey, which usually involves jumping out of the water, to either catch large insects, other fish, or small birds in low hanging branches. This behavior has earned the fish the nickname "water-monkey" (Goulding 1980).

• Key Behaviors
• natatorial
• motile

Communication and Perception

• Perception Channels
• tactile
• chemical

Food Habits

Osteoglossum bicirrhosum are not picky eaters. In a study of their stomach contents, the majority of food items included insects and spiders, most of which were beetles. Also found in the stomachs were crabs, snails, fish, birds, snakes, monkey feces and plant material. It is thought that the snakes and monkey feces were consumed during a flooding. The plant material was probably a result of the predatory behavior of the fish, as explained below (Goulding 1980).

Economic Importance for Humans: Positive

Osteoglossum bicirrhosum are of great economic value to the local fisherman. According to Junk (1976) these fish provide the largest source of protein in comparison to other Amazon fish. Also, because of its low fat content, they are considered the most digestable and least likely to bring about sickness. Osteoglossum bicirrhosum are also of great value in the aquarium business, as noted by the sale of them on many commercial internet sites (Foeshe 2000, Smith 1981).

Economic Importance for Humans: Negative

Unknown

Conservation Status

• IUCN Red List

  Not Evaluated

• US Federal List

  No special status

• CITES

  No special status

Other Comments

Osteoglossum bicirrhosum is thought by the Caboclo people of the Amazon to be very beneficial to women after they have recently given birth. In fact, they are one of the few things women are allowed to eat during this vulnerable point in life (Goulding 1980).

Contributors

William Fink (editor), University of Michigan-Ann Arbor.

Kelly Birchmeier (author), University of Michigan-Ann Arbor.

References

Froese, R. March 7, 2000. "Species Summary for Osteoglossum bicirrhosum" (On-line). Accessed October 25, 2000 at http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=6234.

Goulding, M. 1980. The Fishes and The Forest. Los Angeles: University of California Press.

Nico, L. July 18, 2000. "Nonindigenous Aquatic Species: Osteoglossum bicirrhosum" (On-line). Accessed October 19, 2000 at http://nas.er.usgs.gov/fishes/accounts/osteoglo/os_bicir.html.

Saint-Paul, U., J. Zuanon, M. Villacorta, M. Garcia, F. Noemi. March 2000. Fish communities in central Amazonian white- and blackwater floodplains. Environmental Biology of Fishes, 57(3): 235-250.

Smith, N. 1981. Man, Fishes, and The Amazon. New York: Columbia University Press.