See more of our trusted coverage when you search. Prefer Newsweek on Google to see more of our trusted coverage when you search. In a bizarre twist of evolution, some fish have been found to be able ...

Betta splendens are known for their stunning colors, decorative fins, and tendency to fight. These characteristics are much ...

For some animals, looks and wealth aren't everything. Female mosquitofish prefer mates that had a steady nutritional upbringing over those that suffered a poor start in life with a restricted diet, ...

The animal kingdom is full of unique names. We often use special words to tell males and females apart. For example, a male lion is a king, while a female is a lioness. We call a male deer a buck and ...

In 1975, scientists tried spaying a few hundred female betta fish. We all know what happens to spayed cats and dogs: They become sterile. Betta fish are different. A third of the surviving bettas ...

Learn how the Amazon molly, an all-female fish that reproduces asexually, uses gene conversion to maintain healthy DNA and survive more than 100,000 years without males. Asexual reproduction occurs in ...

Chronic exposure to microplastic fibers causes aneurysms, erosion of surface layers and other serious damage to fish gills, and increases egg production in female fish, a sign that chemicals in the ...