Researchers discover surprisingly high levels of genetic diversity among the colorful male morphs of a freshwater fish.

Bettas were likely the first fish welcomed into human homes. Now, scientists are welcoming them into the lab to learn how genes dictate their appearance and behavior.

After eight weeks of exposure to ecologically plausible levels of methamphetamines, the fish tended to prefer meth-laced water over water without the drug.

The new experiments use standardized methods and video recordings, but some researchers stand by earlier evidence that ocean pH influences coral reef fish’s response to predator cues.

The Penn State University scientist was known for her work on fish’s perception of pain.

The bioluminescent Anomalops katoptron can coordinate its schooling behavior after dark. 

A fossil of a school of fish from the Eocene appears to represent coordinated collective movement.

Watch a Munk’s devil ray breach.

Nearly 50 years after its development, only a handful of creatures have passed the self-awareness exam. A new attempt with fish highlights a debate over the test’s use and meaning.

From cellular self-digestion to the effects of exercise on the brain, our features editor picks her favorite art custom-made for the magazine.

Digesting a big meal takes energy, forcing some minnows to swim in spots at the rear of a school.

How a meal affects minnows' positions in their schools

In the presence of competition, archerfish become more hesitant but accurate shooters.

European perch larvae exposed to environmentally relevant concentrations of polystyrene particles preferred to eat the microplastics in place of prey, according to a study.

The quest to document an ancient sea creature reveals a cyclical chorus of fish songs.

Watch the coelacanth documentary that fish biologist Eric Parmentier and filmmaker Laurent Ballesta were making when they discovered and recorded a world of undersea sound.