A whale shark the size of a school bus swims slowly near the surface of the ocean. Its wide mouth is open, like an enormous net scooping up whatever happens to be around—mostly small fish, …

Sharks star in blockbuster movies as blood-seeking villains, but in reality they’re far more fascinating and complicated than they’re often depicted in pop culture. Based on fossilized …

Meet the real "Nemo," the colorful clownfish. Find out how these fish can reproduce even though all their young are born male.

Freshwater makes up less than 3 percent of Earth’s water supply but almost half of all fish species live in rivers, lakes, ponds, and wetlands.

Pufferfish can inflate into a ball shape to evade predators. Also known as blowfish, these clumsy swimmers fill their elastic stomachs with huge amounts of water (and sometimes air) and blow …

The blobfish went viral with this photo, but underwater they look like a completely different fish. They sustain tissue damage when they're brought from the ocean's depths to the surface.

Meet the newest ‘walking’ fish—a bright red creature of the deep This odd-looking sea toad may look like crochet. But it's one of a hundred species possibly new to science that have been ...

The alligator gar bears no relation to alligators, but with its wide, crocodilian head and razor-sharp teeth, it’s easy to see how this giant fish got its name. The largest of seven known gar ...

What is a barracuda? Barracuda have a formidable reputation as ruthless predators—even depicted in Disney Pixar’s Finding Nemo as the merciless villain that kills Nemo’s mother. …

Find out how these "blowfish" defeat predators by puffing up into inedible balls. Learn how their potentially lethal toxins provide another line of defense.