As a fish swims through water, the dorsal fin stabilizes it and keeps it from rolling over. But over time, many fish have evolved different uses and appearances for these skin flaps.

The oarfish, commonly referred to as the "doomsday fish," was captured on video as it approached beachgoers at Playa El Quemado in Mexico. It's rare to see the species in shallow waters.

The Moorish Idol is a striking marine fish known for its distinctive black, white, and yellow bands and elongated dorsal fin.

A striking fish that lives at the bottom of the Atlantic Ocean has evolved legs – but not just for walking. These appendages are a novel sensory organ like a tongue, which they use to find prey ...

Rare deep-sea anglerfish spotted on ocean's surface for first time 00:44. In what may be the world's first-ever recorded sighting, a black seadevil — anglerfish known for living thousands of ...

Some types of “walking” fish called sea robins can use their taste bud-covered legs to detect prey buried beneath the sandy covering of the seafloor.

This robot fish is "as silent as a spy" — and could help researchers learn even more about the ocean 01:05. The mysteries of the ocean abound. And now, a group of student researchers is trying ...

Ocean pout live in frigid waters from Labrador in Canada to North Carolina and have evolved a blood protein that serves as antifreeze. When you purchase through links on our site, we may earn an ...

But video evidence from the deep ocean suggests that some species of anglerfish — the nightmarish deep-sea fish with bioluminescent lures — live their whole lives upside down.

As a fish swims through water, the dorsal fin stabilizes it and keeps it from rolling over. But over time, many fish have evolved different uses and appearances for these skin flaps.