It may sound too bizarre to be true, but the Amazon molly (Poecilia formosa), a fish that inhabits rivers, lakes, and swamps ...

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 ...

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, ...

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 ...

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 ...

Female mosquitofish are not only bigger than the males, they have bigger impacts on freshwater ecosystems. In a controlled study conducted in experimental ponds, researchers found dramatic differences ...

Female fish can breed a new species if they aren't choosy about who is Mr. Right. Fish will mate with a species outside their own if the male's coloring is attractive enough or if the female can't see ...

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 ...

There are more than 34,000 species of fish on our planet. It can be tricky to tell the age or gender of a fish, but biologists have come up with a few different ways to find out. My friend Paul ...

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 ...