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 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 ...

In a Swedish lab, Alexander Kotrschal has deliberately moulded the intelligence of small fish called guppies. From a starting population, he picked individuals with either unusually large or small ...

Guppies, which are also called millionfish, feed on mosquito eggs and larvae. This tropical, aquarium fish species is also highly adaptable to a number of environmental and ecological conditions ...