Copper is Antifouling

Biofouling is the gathering of undesirable materials, such as algae and barnacles, on wet surfaces, like the undersides of boats. It can lead to intake pipes getting blocked and ship hulls being completely coated with materials that create drag as the boat moves through the water. In the 18th Century, copper cladding was used on wooden ships to combat biofouling and attack by the notorious Teredo Worm. Today, copper-nickel alloys are used to protect offshore platforms, boat hulls, seawater pipework and desalination units. Modern fish farms are starting to use copper alloy cages to hold fish while keeping out predators. These require minimal maintenance and provide a safe and healthy environment for fish to grow.
fence under water