This sounds like something out of “The Little Mermaid”, except more festive. The Chattanooga, Tennessee Aquarium has an electric eel that can power lights on a Christmas tree. They call him “Miguel Wattson” and he has his own Twitter page.
Here’s how it works. The aquarium hooked up a special system to Miguel’s tank to pick up his charges. He releases low-voltage blips of electricity when he’s trying to find food.
People outside the tank can HEAR some of those charges, and then SEE the lights on a nearby tree flicker and flash.