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

Invasive Fish Species


Scientific Name

Lepisosteidae family - Visit ITIS for full scientific classification. 


  • Large, freshwater fish with a slender, cylindrical body.
  • Gars have hard, bony, scale-less heads and snouts with elongated jaws lined with long, sharp teeth.
  • They have diamond-shaped and non-overlapping scales.
  • Patterns and coloration can vary between the 7 different species: Alligator, Shortnose, Longnose, Spotted, Cuban, Florida, Tropical.
  • The largest gar reported was about 10 feet and 350 pounds. 
  • Gars are adapted to live in harsh environments as their swim bladders are connected to their throats.
  • They can use this swim bladder as a lung to breath air, surviving waters with low oxygen levels.
  • Gars are usually found in low flow areas with a lot of vegetation, and they prefer warm, shallow pools in rivers and lakes. 
Invasion Pathways and Distribution
  • Gars are popular aquarium and game fish.
  • They can spread when pet owners release them into the wild.
  • They can also spread when they're introduced for sport fishing, and when they escape from fish farms.
  • Native ranges differ between species.
  • The Alligator, Shortnose, Longnose, Spotted, and Florida Gars are all native to the U.S. None of the species are currently found in California.
  • See USGS for current U.S. distributions. 
Life History
  • Mating can occur when the water temperature is warmer than 68 degrees F.
  • Depending on the species, spawning will occur over a bed of vegetation or gravel, and the young fish will then attach to an object to begin development.
  • Aggressive top predators that feed on a wide variety of animals including: fish, crabs, birds, small mammals, turtles, etc.
  • Gars themselves have few natural predators, giving them great potential to prey upon, and outcompete native species. 
References and Useful Links

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

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