Why Do Guppies Jump Out Of Fish Tanks?

Suicidal move may actually be a survival instinct.
Karin Heineman, ISTV Executive Producer

The cute, colorful, low-maintenance guppy seems like a great pet, until it makes a fatal jump out of the fish tank and onto the floor with no one to rescue it. Now, research suggests that the suicidal jump that many guppies make may actually be a tragically misplaced survival instinct.

Daphne Soares, a neuroscientist at the University of Maryland in College Park, has been studying fish behavior for years and said there is one major drawback to guppies.

“We kept having this problem that the fishes kept jumping out of the water, so they jumped out of the tanks in the fish room, they jumped out of the tanks in the holding room. When they had containers, we had fish just spontaneously jump out,” said Soares.

The day a guppy landed in Soares' cup of iced chai, she decided to get to the bottom of their strange behavior.

“I said, ‘OK that’s enough. We’ve got to figure this out. How are they doing this? Why are they jumping so much?’ And you know, how do they jump so well, and so often,” recalled Soares.

Using high-speed cameras, Soares observed behavior never reported before in fish: the guppies actually prepared to jump by first backing up and then hurtle themselves into the air. They are able to jump 7 times their body length at more than 4 feet per second.

But guppies don’t leap out to catch prey or escape predators. Rather, their jumping probably serves a crucial evolutionary role.

“They’re not committing suicide; they’re trying to find new waters and new places to live,” said Soares.

Soares’ best advice if your kids insist on a pet guppy is to put a lid on their tank, "because they are probably going to jump,” she said.

The next step is for researchers to go to Trinidad where their guppies are from and study the fish in their natural environment.


Get Inside the Science:

Why do guppies jump?

High speed video of guppy jumping

Soares Lab, University of Maryland

Author Bio & Story Archive

Karin Heineman is the executive producer of Inside Science TV.