Researchers working on energy efficiency need look no further than the rivers of South America for inspiration. A fish called the Sternopygus macrurus uses electric fields to sense its environment and is able to dim its signals to save energy during the day when it’s resting.

“This is a really expensive signal to produce. The fish is using up a lot of its energy budget,” neurobiologist Michael Markham at the University of Texas at Austin told Wired. “These animals are saving energy by reducing the strength of the signal when they are not active.”

Markham is the lead author of the paper on the S. macrurus, which appeared in PloS Biology. His team reveals that S. macrurus is just one example among thousands of fish and other oceanic creatures that have built-in energy-efficiency systems, allowing them to “conserve power” when they don’t need it by reshaping the charged-molecule channels in their electricity-producing cells.

This particular fish proved to be an excellent research subject because its electrical discharge is fairly regular, while other fish put out signals that can vary a lot more. All fish can generate electricity using a cell called an electrocycte, which manipulates the amount of charged sodium and potassium ions that they allow to flow in and out of their bodies.

Green energy researchers aren’t the only scientists who can stand to learn something from the S. macrurus and similar sea creatures. The way that the fish’s cells reshape their membranes may help scientists understand the kinds of electrical malfunctions that cause disorders like epilepsy in humans.