Care
The Swan Mussel is a large species of freshwater mussel, typically found in lowland lakes, canals, and quiet river backwaters with low current, muddy or silty substrates, and sparse vegetation. Here, these aquatic bivalve molluscs burrow into the soft substrate, leaving just their two siphon tips exposed. The siphons are tube-like structures that are positioned at the posterior edge of the mantle cavity which allow the mussel to breathe, feed, excrete, and reproduce. Water is drawn in through the inhalant siphon, and is moved over the gills for respiration. During this process, the Swan Mussel filter feeds on finely suspended particles, and the water is then forcefully expelled through the narrower exhalant siphon. This species is best maintained in a unfiltered wildlife pond situation, where the water quality is good but there are plenty of suspended infusoria particles. They are not recommended for clear, heavily filtered ponds, as such environments will not provide a suitable ongoing source of nutrition. Due to the specialised reproductive cycle (see Breeding section below), it is not always advisable to keep Swan Mussels alongside fish, as there is the possibility of skin damage and secondary infection. The most appropriate housing is therefore mature, unfiltered wildlife ponds with soft substrate and gentle water movement (some current is preferable in order to provide adequate dissolved oxygen, but it should not be too vigorous). It should be noted that although these bottom dwellers filter feed, they also obviously excrete waste products from this process, and will not "clean" the water in the same way that a filter does. They require a continuous source of nutrition and appropriate conditions if they are to thrive.
Feeding
Filter feeders which require an ongoing source of infusoria within their environment.
Breeding
In the wild, reproduction of the Swan Mussel depends on the presence of suitable fish hosts - usually Brown Trout (Salmo trutta), Dace (Leuciscus leuciscus), European Eel (Anguilla anguilla), Perch (Perca fluviatilis), Pike (Esox lucius), Stickleback (Gasterosteus aculeatus), Tench (Tinca tinca), or Zander (Sander lucioperca). During the spring time, female Swan Mussels produce eggs and brood them inside specialised chambers in their gills known as marsupia. Males release their sperm into the open water, which the females draw in via their siphon. This then fertilises the eggs, which develop into parasitic larvae known as glochidia, and these are released into the water and carried by currents until they come across a suitable host. The glochidia attach themselves to the outside of the fish and then encyst, feeding off the body mucus of the fish. After several weeks, they will drop off and find a suitable place on the substrate in which to develop into adult mussels.
