Piaractus
Piaractus is a genus of Sägesalmler from tropical South America. The word meaning of the genus Piaractus comes from ancient Greek and means piar πιαρ - fat and AKTOS ἄκτος, - bear, so Fetträger.
System
The genus Piaractus consists of two types:
- Piaractus brachypomus ( Cuvier, 1818)
- Piaractus mesopotamicus ( Holmberg, 1887)
Piaractus was first described in 1903 by Eigenmann. 1951 Goslin bordered from the genus due to the anatomy of their teeth, the adipose fin and bone characteristics of the other Sägesalmlern. Nelson found 1961 more characteristics as the morphology of their swim bladder and features of the internal anatomy.
Features
Piaractus is an original genus of Sägesalmler, which differs from the genus Colossoma characterized in that the front part of the air-bladder is smaller than the rear, and the swim bladder muscle has only one band. Other characteristics are six or more hochspezailisierte teeth in the lower jaw - main sequence, an anal fin with 28-30 fin rays.
Dissemination
While P. brachypomus inhabited the equatorial flood plains of the Amazon and Orinoco, P. mesopotamicus is endemic in the south of the continent in the river basin of the Rio Paraná and Rio Paraguay. Both species are highly specialized adapted to the ecological system of floodplain forests and come out of this habitat is not present in the wild. So they do not occur in blackwater rivers such as the Rio Negro.
Way of life
Both species show an omnivorous diet and are characterized by rapid growth. The Indian word " Pacu " from the Tupi language means as much as fast eater. While they feed mainly on plankton in youth, adult specimens eat insects, nuts, fruits and seeds. Although P. brachypomus and P. mesopotamicus have the same nutritional habits, they occupy different ecological niches in the waters in which both occur. While P. brachypomus is most active early in the morning, eats P. mesopotamicus mainly at dusk. During the spawning period, the animals migrate to the upper reaches of rivers to spawn in calm water sections. This long hikes can be undertaken. For keeping in aquaculture special feeding techniques have been developed.
Economic Importance
Piaractus mesopotamicus are important food fish that are kept in aquaculture. Furthermore, both species are popular because of their high weights Angel fish, even in countries where they were introduced as an alien species. Also known as ornamental fish in the aquarium trade are the species of the genus Piaractus of some economic importance. They are sold under the names " vegetarian piranha ", Pacu, Tambaqui, Pirapitinga or Silver Dollars available. You will still be exposed in many countries and can cause damage as an invasive species in a foreign ecosystem.