Dominant males of an Indonesian species of fish turn black during periods of heightened aggression, scientists have discovered. Their blackened markings, which quickly emerge at the start of a ...

Among aquarium enthusiasts who keep bettas, it is usually the male fish that are known as the "colorful ones." Oftentimes the males are favored over the females not only for their color, but also ...

Why does a Caribbean angelfish sometimes resemble its Indo-Pacific cousin, even though they have never lived in the same ...

A newly discovered visual system in deep-sea fish could allow them to discern predators from prey in the low-light conditions found at the bottom of the ocean, new research suggests. A team led by ...

New research reveals signs of highly sensitive color vision in fish that live in the abyss beyond sunlight's reach An international team of researchers discovered a previously unknown visual system ...

Similarities in how different organisms look can indicate a close evolutionary relationship. Conversely, great differences in appearance can suggest a very distant relationship, as in many adult ...