These days, all fish have teeth. The shapes of their teeth vary according to diet, ranging from the little pegs of goldfish ...

Why does a Caribbean angelfish sometimes resemble its Indo-Pacific cousin, even though they have never lived in the same ocean? Why do coral reefs harbor such a wide range of stripes, spots and ...

A study published in the Nature journal alters how the evolution of fish has been historically understood. Fossilized fish and other sea creatures have often been pivotal in new scientific discoveries ...

In Lake Malawi, hundreds of species of cichlid fish have evolved with astonishing speed, offering scientists a rare opportunity to study how biodiversity arises.

The Amazon molly reproduces without sex. A genomic copy-and-paste trick called gene conversion may explain how it avoids evolutionary meltdown.

Editor's note: All opinions, columns and letters reflect the views of the individual writer and not necessarily those of the IDS or its staffers. We’ve all seen this poster in our middle school ...

Reef fish in different oceans often develop similar color patterns because evolution explores the same set of biological ...

A newly discovered golden cave fish in southwestern China is giving scientists an unprecedented look at evolution in action.

Get your news from a source that’s not owned and controlled by oligarchs. Sign up for the free Mother Jones Daily. In the world’s waters, fish are making a quiet, biological retreat. The once simple ...