California Aquatic Invasive Species (AIS)
University of California
California Aquatic Invasive Species (AIS)

Invasive Fish Species


Scientific Name

Characidae family - Visit ITIS for full scientific classification. 


  • Freshwater fish with laterally compressed bodies.
  • Their lower jaws stick out farther than their upper jaws, and both jaws are lined with a single row of sharp teeth.
  • Color and size vary widely between the different species, but Piranhas typically grow to about 12 inches and up to 2 pounds.
  • Popular aquarium fishes. 
  • Found in murky waters of tropical rivers and streams. 
Invasion Pathways and Distribution
  • Native range is within tropical America.
  • No established populations in the U.S., although there have been multiple reports of Piranhas in California within the past 30 years, most likely due to aquarium releases.
  • See USGS for current distributions. 
Life History
  • Little is known about the reproductive behavior of Piranhas in the wild.
  • Mating usually starts at the beginning of the rainy season.
  • Piranhas swim in circles to attract mates, both parents guard the eggs until they hatch, and the young fish live near vegetation until they mature. 
  • Piranhas are aggressive predators that feed on a wide variety of animals.
  • They have few natural predators, and if introduced they have the potential to deplete native populations by consuming and outcompeting natives for resources. 
References and Useful Links

For references by category and links to other useful AIS sites see our LEARN MORE page.

Top of page

Webmaster Email: