A betta fish (Betta splendens) photographed in Lincoln, Nebraska. Also known as Siamese fighting fish, they originally hailed from Southeast Asia but are now popular pets found in …

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 ...

A shadowy shape is visible in the distance, just under the surface of the ocean. The shadow swims closer, revealing itself to be a shark—an incredibly massive shark. Weighing as much …

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 …

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.

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

Soar into the world of flying fish. Find out how their amazing talents—that may be used to avoid predators—can sometimes get them in trouble.

Taking a blobfish out of water is like “heating something that’s glued together and the glue starts to melt.” The blobfish went viral with this photo, but underwater they look like a ...

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 ...