Types of Fish

You may think you know what a fish is, but this group of animals actually has a very specific definition. To be a fish, the animal must have specific physical features:

  • Head and skull
  • Gills throughout its life
  • Primitive spine
  • Fin-shaped limbs without fingers

Fish biologists have described more than 30,000 species of fish in the world. Visit NPSpecies to see what species of fish are found in national parks.

Scientists classify fish into two major groups: the jawless (Agnatha) fishes and the jawed (Gnathastomata) fishes.

Jawless Fish

Lampreys and hagfish.

Fish in corals
Jawed Fish

Sharks, skates, rays, sharks and bony fish.


Native Fish in Parks

National parks contain about 60% of all native freshwater fish species that occur within the United States. Many unique, native fish make their homes in national parks.

  • Devils Hole pupfish is the most geographically restricted vertebrate species in the world. That’s a fancy way of saying it lives in only one isolated cavern in the world. You can find it in a warm spring pool in Death Valley National Park, the hottest, driest valley in North America.
  • Mohave tui chub is an endangered minnow, a common name for freshwater fish. Originally, this fish only lived in the Mojave River, but now its largest population is in the Mojave Chub Spring (MC Spring) in Mojave National Preserve.
  • Sheefish, also called inconnu, are rare everywhere except in the Kobuk River in Kobuk Valley National Park. These whitefish can grow as long as 1 meter and weigh up to 60 pounds!
  • ‘O’ opu are a group of five, freshwater gobies native to the streams of the Hawaiian Islands. There are more than 2,000 species of gobies, and they’re usually very small and are generally bottom-dwellers. You can watch them swimming in a stream at Kalaupapa National Historical Park.
  • Sockeye salmon are a critical part of the ecosystem at Lake Clark National Park and Preserve. Each year, 372,000 sockeye swim up the Newhalen River, returning to the creeks, streams, and lakes where they were born.
  • Garibaldi is the California state fish. Visitors to Channel Islands National Park in Southern California commonly see this species of damselfish in kelp forests. However, fishing for garibaldi is illegal; it’s a protected species.

Last updated: February 13, 2018