### Identification The Asian Clam is a small, plump bivalve, rarely exceeding 50mm (about 2 inches). Its most striking field mark is the sculpted, concentric ridges that ring the shell like a miniature washboard—much more prominent than the smoother shells of native fingernail clams. The exterior typically wears a yellowish-green to light brown periostracum, but the real treasure is found inside: the nacre (inner shell) is a lustrous, deep royal purple. Unlike native mussels, which are often elongated or flattened, *C. fluminea* is distinctly triangular and "inflated" in profile.
### Habitat & Range Native to Southeast Asia, this hardy traveler has conquered freshwater systems globally. You’ll find them in lakes, ponds, and slow-moving rivers, specifically favoring sandy or gravelly substrates where they can easily burrow. They are sensitive to low oxygen, so they rarely inhabit stagnant, mucky depths, preferring the well-aerated shallows of the littoral zone.
### Behaviour Observing a colony is a lesson in sheer density; in optimal conditions, you may find thousands of individuals packed into a single square meter. They are hermaphroditic and prolific breeders, releasing "pediveliger" larvae that use sticky mucilaginous threads to hitch rides on boat hulls or waterfowl. In the field, look for their twin siphons poking just above the sediment, rhythmically pulsing as they process the water column.
### Diet As active filter feeders, these clams act as biological vacuums. They pump water through their gills to extract phytoplankton, floating algae, and organic detritus. By removing vast amounts of suspended matter, a large colony can actually increase water clarity, though this often starves out native species that rely on the same food source.
### Fascinating Fact The Asian Clam is a biological anomaly: it can reproduce via androgenesis. In this rare form of "all-male" cloning, the egg’s genetic material is discarded, and the resulting offspring is a perfect genetic clone of the father!