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.

Prefer Newsweek on Google to see more of our trusted coverage when you search. How people respond to stressful situations can say a lot about their personalities—and it turns out the same is true of a ...

Tiny guppy fish change their eye colour to warn off rivals, new research shows. When facing an opponent, Trinidadian guppies rapidly turn their irises from silver to black before attacking their ...

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 ...

NEWPORT NEWS, VA.? There’s no coat to brush and fluff. No nails to clip, or teeth to brush. Forget obedience training because they don’t respond to verbal commands. A Half Black AOC male guppy is ...

Most anglers reach for large bait when targeting big fish. We did the opposite. Tiny live guppies and minnows hit the water, and the results were surprising. Sometimes small bait triggers big ...

Bringing a fish home for your child might sound like a small decision, but it’s actually a big step into responsibility, bonding, and joy. Among the most popular pet fish, goldfish and guppies top the ...

Trinidadian guppies behave like matadors, focusing a predator's point of attack before dodging away at the last moment, new research shows. Trinidadian guppies behave like matadors, focusing a ...