Fish that were thought to be eliminated from Port Sulphur waterways in Louisiana have unexpectedly returned, reported The Times-Picayune. Tilapia, a fish often found on dinner plates, has reappeared ...

Clownfish off the Papua New Guinea coast are shrinking. The Conversation spotlighted a troubling survival adaptation that the colorful fish — made popular by the film Finding Nemo — are making to ...

Two species of small, deep-dwelling fish called pearlsides possess eye cells that break the rules of vertebrate vision, combining features of rods and cones into a single hybrid photoreceptor never ...

Learn how cleaner wrasse used a mirror and even dropped food to test their reflections, a behavior linked mostly to mammals.

(CNN) - There’s a strange underwater mystery in the Florida Keys. Fish there are swimming in circles until they die. Now, researchers are racing to figure out what’s causing the bizarre behavior and ...

Researchers identified a new freshwater fish species in South Africa after years of genetic testing and analysis.