Guppy lives in Taylorsville, N.C., and works as a middle school custodian during the week. On the weekends, he competes against other 50-and-overs on the PBA Senior Regional Tour.

And they might as well. After all that hard work evolving large-brained guppies, they now have more than 5,000 of the little critters. “It takes over an hour just to feed all the fish,” Kolm says.

Researchers found that it was easy to breed guppies with bigger brains, but the fish had smaller guts and also produced fewer progeny. The results serve as experimental evidence of evolutionary ...

Bill Carwile knows what makes a good guppy. One of seven senior judges for the International Fancy Guppy Association (IFGA) and a best-of-show winner many times over, Carwile has been ...

The way guppy fish behave suggests they can be tricked into believing holes are larger or smaller than they really are – but they don’t always interpret the optical illusions in the same way ...