Glochidium

As Glochidium is called the parasitic larva of fish of the families river mussels ( Unionidae ) and freshwater pearl mussels ( Margaritiferidae ) in the superfamily freshwater mussel similar ( Unionoidea ). The in the gills of the mussel females (eg the swan mussel ) fertilized eggs grow into Marsupien to glochidia. This anchor themselves with hooks and adhesive threads on the shell valves. After some time, they settle into the free water by they move through movements of their shell. The glochidia then attach themselves to a fish where they live 2 to 3 months as parasites in the gills or on the fins of their hosts. There they are evolving, and then fall to the ground. Only then did they evolve to a filtered clam.