Mussels are suspension feeders--they feed by actively filtering particles from the water.The main food source of the blue mussel is phytoplankton, but they will also feed on other suspended organic material in the water. Cilia are used to move particles into their mouths by creating water flow. The labial palps in adult blue mussels are able to sort the particles, separating food from the indigestible material, which is then rejected through the gills. Click on the image above to identify the internal anatomy of a mussel.