Golden mussel

Limnoperna fortunei · Aquatic life

Whole animal · Photo: Andrea Gantzer / CC BY

InvasiveMollusk (mussel, clam, snail)

Also called Limnoperna, Limnoperna fortunei

State listing

Idaho: Prohibited invasive species
Oregon: Prohibited

How to identify Golden mussel

Small mussel usually under 1 1/2 inches
Golden yellow to brown shell, smooth and glossy
Shape like a small sea mussel, without the flat bottom of a zebra mussel
No shelf (septum) inside the pointed end of the shell
Attaches to hard surfaces in clumps with byssal threads

Similar species

Zebra and quagga mussels have a small shelf inside the pointed end and are usually striped. Asian clams do not attach and have strong ridges.

Profile

Season	Spawns in warm months.
Starts	Spawns in warm water
Depth	Shallow to deep hard surfaces
How it spreads or reproduces	Microscopic larvae in water on boats, trailers and equipment; adults attached to watercraft
Habitat	Not known to be established in Idaho, Oregon or Wyoming, though in April 2026 Oregon inspectors stopped a boat from California fouled with golden mussels. In California since 2024, now through the Sacramento San Joaquin Delta and waters connected to the California Aqueduct; attaches to rocks, pipes, screens and boats in lakes, reservoirs and canals.

Why it matters in a lake

A watch species. Like zebra and quagga mussels it clogs pipes, intakes and irrigation systems, and it tolerates softer, lower calcium water. Report any suspected find to the state agency right away.