A polluted river in Mexico may be scrambling the love lives of two small fish species — so much so that it may be erasing the line between them. Downstream of the town of Calnali, in central Mexico, ...

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. A Stanford-led study found that the two swordtail fish ...

Hundreds of dead fish have washed up on the Barnai River in northern region of the country, raising fears of severe water pollution and prompting residents to avoid contact with the water. The river, ...