Living fossils are live entities — trees, bugs, animals, fish — that exist today in nearly the same form as they did millions of years ago. The coelacanth is considered the most famous living fossil fish, but it isn't the only one. Here are some other fossil fish that have swum under the radar [source: Krock].
- Bowfin. Aka dogfish, mudfish and grindle, bowfins are American freshwater fish found in the Mississippi River basin and the Great Lakes, among other sites. Fun facts: Bowfins are fierce, and will eat other fish, frogs, snakes, small mammals and even other bowfins. They also can go without eating for up to a year because they have low metabolisms.
- Gar. These freshwater fish favor warm water; they're generally found in the southern U.S., Central America, Mexico and the West Indies. Like bowfins, the long-jawed gars are vicious and will eat other fish. They're also apt to simply attack any fish in their way, even if they don't intend to eat them. Fun facts: Don't eat gar eggs — they can kill humans and other warm-blooded vertebrates. Gars themselves are also inedible.
- Hagfish. They're mud-dwellers in the Atlantic and Pacific Oceans, and they are some of the most disgusting-looking fish in the world. Popular in South Korea, they look a bit like eels and have no eyes or jaws. Creepy fun fact: Hagfish dine on weak or dead fish. They do so by swimming into the fish's stomach via the mouth, then consume the fish from the inside out.
- Sturgeon. Sturgeon, which can be found in both freshwater and saltwater in North America, are enormous. Stretching up to 20 feet (6.1 meters) and weighing up to 400 pounds (181 kilograms), they're the largest freshwater fish in the world. Sturgeon definitely look like fossil fish, sporting odd, retractable mouths and armorlike skin. Fun facts: Sturgeon can live to be 100. The beluga sturgeon, found in the Caspian Sea, is famed for its caviar.