A primary urge led to the evolution of the fish's skill, and that is hunger.
"The predominant impression from our field work in Thailand over several years is that there is very little to actually shoot at, so it's important for the fish to be efficient," says Stefan Schuster of the University of Bayreuth in Germany. "It pays to be able to powerfully hit prey over a wide range of distances."
Usually the fish shoot water at a surprised victim, such as a little lizard on a twig above the water. The stunned lizard is forced off the twig and into the water, where the fish gobbles it up.
Coming soon to a store near you could be water nozzles modeled after the fish's natural mechanism for controlling water. Adjustable jets are big business in many industries, including medicine.
Fish Garden, Even Do Weeding
The scientists must first overcome some challenges that clearly the fish resolved through their evolution some time ago.
"The biggest problem is how to modify the abrasive properties of a jet," Schuster says. "Usually this is done by modulating the release pressure or by varying the abrasives added to the jet. We are not aware of someone actually using a dynamically adjustable valve."