Guppies are beginner-friendly, low-maintenance fish that thrive in a 10-gallon tank, with a peaceful temperament and omnivorous diet. Males are smaller with vibrant colors, while females are larger ...

From our perspective, guppies lead simple lives—eating, reproducing, and, after a couple of years, dying. Apply a little evolutionary pressure, though, and they can evolve larger brains that make them ...

Scientists have long suspected that big brains come with an evolutionary price — but now they've published the first experimental evidence to support that suspicion, based on their efforts to breed ...

Guppies are a small, pretty species of fish that are extremely popular for home aquariums. While they’re fun in captivity, in the wild they can cause major trouble. Native to South America, guppies ...

A long-term fish experiment reveals how a mechanism called density dependence, in which the population growth rate slows as the number of individuals rises, affects population dynamics on time scales ...