Clam
Freshwater Golden Clam
Corbicula fluminea · also called Asian clam
These illustrations are AI-generated, not photographs, and are not to scale. They show what to look for; they are not a substitute for an expert identification.
How to identify it
Size: Usually 1 inch or less.
- A thick shell shaped like a rounded triangle.
- Heavy, evenly spaced ridges running around the shell like growth rings.
- Yellow-green to golden-brown on the outside.
- Pale purple or bluish-white on the inside.
- Fine teeth along the hinge where the two halves meet.
Don’t confuse it with
Native fingernail and pea clams are small, thin and smooth, without heavy ridges. Native mussels are much larger.
Where it came from
Native to Asia, Africa and Australia.
First found in North America on the Pacific coast in the early 1900s. In the Great Lakes it is often found near warm-water discharges such as power plants.
Earliest dated Indiana record: 1964, the Ohio River below New Harmony, Posey County. This is the oldest dated record in the USGS non-native species database, not necessarily when it first arrived.
Why it matters
It can build up in very large numbers, clog water intakes and compete with native clams and mussels for food.
Indiana law
Prohibited under Indiana's mussel rule (312 IAC 9-9-3). It is illegal to import, possess or release it into public or private waters. Taking one and killing it immediately does not break the rule. Indiana's rule calls it the Asiatic clam. Indiana DNR’s page.
If you find it
- Don’t move it. Before leaving the water, remove all plants, mud and debris and drain all water from your boat, motor, live well, bilge and trailer. Carrying plants listed in Indiana’s Aquatic Plant Rule on vehicles, boats or trailers is illegal and can bring fines. Clean boater tips
- Never release bait or pets. Don’t dump bait, aquarium animals or water-garden plants into any lake or stream. Put unused bait in the trash.
- Report it. Take a photo, note where you saw it, and report it through EDDMapS or the GLEDN phone app, or contact Indiana DNR’s aquatic invasive species program at 317-234-3883 or ais@dnr.IN.gov. Experts there can confirm what you found.
- Ask before removing or treating. On public lakes, any control of aquatic plants — chemical, mechanical, physical or biological — needs an Indiana DNR aquatic vegetation control permit. When a permit is needed
Indiana lakes where it has been recorded
1 Indiana lake on this site has a record of this species.
Steuben
A lake that is not listed may still have it. Records exist only where someone found the species and reported it, so “not recorded” does not mean “not present.”
Lake records: Midwest Glacial Lakes Partnership Conservation Planner; underlying records from the USGS Nonindigenous Aquatic Species database.
Sources
- USGS Nonindigenous Aquatic Species: Asian clam fact sheet
- Indiana DNR: Aquatic invasive species, invertebrates
- Indiana DNR: Aquatic invasive species possession rules (312 IAC 9-9-3)
Earliest dated record: USGS Nonindigenous Aquatic Species database.