Fish in a polluted Mexican river may mate with the wrong species, leading to hybrid offspring

The byproducts of modern society appear to be messing with the love life of two tiny fish species that have long coexisted in Mexican rivers.

Tiny ancient fish fossil with preserved brain offers clues to early fish evolution

Over 300 million years ago, a minnow-sized fish died and fell to the bottom of a prehistoric swamp near the village of Trawden, Lancashire, in northwest England. The remains of this tiny fish—known as ...