also known as: glochidia
Margaritifera are bivalve molluscs whose larvae (glochidia) temporarily parasitize the gills of freshwater fish. They are visible as white spots on the gills, which a microscope shows to be larval bivalve shells. The molluscs grow, then drop off when they mature. They can cause disease if present in high numbers on the fish. The mollusc uses the fish as a source of transport to move its larvae around.