Invasive Zebra Mussels Detected on Aquarium Marimo Moss Balls

On August 5, the Washington Department of Fish and Wildlife (WDFW) received notification from a local wholesale aquarium company in Renton of possible invasive freshwater mussels on a shipment of Marimo moss balls (Aegagropila linnaei). Moss balls are a commonly used decorative algae in aquariums and water gardens. Lab testing confirmed the mussels were zebra mussels (Dreisena polymorpha), a prohibited aquatic invasive species in Washington that, if established in local waters, would be capable of causing significant infrastructure and environmental damage. Zebra mussels and a close relative, the quagga mussel, are not known to be established in Washington.