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 ...

The guppy studied is the tiny fish in the bottom-left corner. Also shown are the two predators researchers used to stress the guppy out: a heron and a blue acara cichlid. The guppy studied is the tiny ...

Guppies can be fooled by optical illusions into believing objects are smaller or larger than they really are. This suggests they might not always make the best choices in their natural environment.

Five minutes in the life of a guppy, in the terrible spring of 2015: You’re swimming around with your friends in a tank. You’ve been here for days. Food falls from the sky. Everything is fine. Then ...

Duping a guppy is easier than duping a ring dove — at least when it comes to a classic optical illusion.

Are you new to fish-keeping and planning to start an aquarium? Well, while keeping an aquarium at home needs efforts and time ...

Tiny fish called Trinidadian guppies turn their eyes black to warn other fish when they are feeling aggressive, new research shows. Tiny fish called Trinidadian guppies turn their eyes black to warn ...

When Robert Heathcote dips his head into the rivers of Trinidad, he’ll often see little black dots moving through the water, even when it’s murky. Those dots are the eyes of small, inch-long fish ...

Mosquitofish and guppies, though known to be cannibalistic in captivity, are extremely unlikely to be cannibals in wild settings, and the rare instances of cannibalism in these fish are likely due to ...

A large group of yellowfin tuna swimming off the coast of Italy. Like all fish, they sleep, but it's not like human sleep. Giordano Cipriani/The Image Bank via Getty Images From the goldfish in your ...

To the surprise of the scientists, populations of a South American guppy were spotted at the Fernando de Noronha archipelago, a volcanic island in the South Atlantic. Even if being easily adaptable ...