 Sperm is released by the male directly into the water and enters the female via the incurrent siphon.After fertilization, the eggs develop into a larval stage called a glochidium (plural glochidia), which temporarily parasitizes fish, attaching themselves to the fish's fins or gills.Prior to their release, the glochidia grow in the gills of the female mussel where they are constantly flushed with oxygen-rich water.