Mussels play a crucial role in maintaining good water quality in a garden pond, serving as natural water filters. Native mussel species are best suited for garden ponds as they are hardy and low-maintenance. If you keep bitterlings in your pond, mussels become essential, as these fish engage in a symbiotic relationship with mussels for breeding. The Great Pond Mussel can reach a significant size but grows slowly, taking approximately eight years to reach maturity.
Suitable Mussel Species for the Garden Pond
For garden ponds, choose native mussel species that are well-suited for the environment, as they are efficient water filters. The Little Pond Mussel, Great Pond Mussel, and Painter’s Mussel are good choices. The Great Pond Mussel, in about eight years, can grow to approximately 25 centimeters in size. The Painter’s Mussel is slightly smaller but can live up to 15 years.
Conditions for Keeping Mussels in the Garden Pond
To establish mussels in your garden pond, specific conditions must be met. Pond mussels bury themselves for protection and pre-filtering, digging up to two-thirds of their length. They require a sandy or fine-gravel pond bottom with a minimum thickness of 15 centimeters. Mussels filter water to obtain nutrients, feeding on suspended particles in the water, which helps counteract algae growth. After feeding, mussels burrow into the sediment for digestion and rest. The pond bottom should not be crisscrossed with roots. Plant your pond plants in baskets to avoid this. Painter’s mussels prefer to stay at the pond’s edge, obtaining food through water movement, so they should be at a sufficient distance from the plant zone. Mussels move slowly and require a current to obtain food. Thus, a pond with a stream is ideal.
Mussels do require pond plants, but the plants should not obstruct water flow. In the summer, the water should not become too warm, which is ensured by a pond depth of at least 80 centimeters. Larger and deeper ponds provide favorable conditions for mussels.
To ensure mussels can filter enough food, calculate at least 1,000 cubic meters of water volume per mussel. The water should not be treated by technical filters and should not be overly clean, as this could deprive the mussels of their food source. In natural ponds, filters may not be necessary if mussels are present. Additionally, if you have an adequate number of plants, a filter may not always be required with mussels in the pond.
Mussels feed on suspended particles in the water, mainly waste materials from plants and fish in the pond. Mussels are essentially waste processors in your pond, contributing to water purification. If your pond is newly established or the water is very clear, mussels may not find enough food. To ensure an adequate food supply, you can supplement their diet with phytoplankton or spirulina. While mussels do not eat algae, they help counteract algae growth by removing an essential foundation for algae.
Coexistence of Mussels with Other Pond Inhabitants
Mussels do not pose a threat to other pond creatures, as they do not compete for food and lack teeth. They are beneficial to other pond inhabitants, serving as waste processors and water filters. However, if there are too many fish in the pond, they can disrupt mussels during filtration. Mussels close when they sense danger, so, to maintain them, you should have one mussel per pair of bitterlings in the pond.
Mussels can overwinter well by relocating to deeper pond areas. To facilitate this, place them in a water lily basket with a sand layer at least 20 centimeters deep. Do not bury the mussels in the sand to prevent injury. Ensure that the location does not freeze. Mussels are less active in winter, but when the weather warms up, move them to a shallower area of the pond. Remove them from the water lily basket and place them near the pond’s edge, away from the plants. The mussels will burrow into the sediment again.
Alternatively, you can overwinter your mussels in an aquarium filled with at least 20 centimeters of sand. Fill the aquarium above the sand with pond water. The move to the aquarium should occur when the water temperature drops below 20 degrees Celsius. The aquarium should be placed in a bright, cool location, avoiding temperature fluctuations. Store pond water in a rain barrel, as every two weeks, you should change some of the water in the aquarium to ensure there is enough food for the mussels.
Reproduction of Mussels
If you do not have bitterlings in your pond, mussels will not reproduce. Bitterlings and mussels depend on each other for reproduction. Mussels are hermaphrodites, possessing both male and female reproductive cells. Bitterlings lay their eggs in the gill chambers of mussels. When the fry hatch, they attach to the mussel’s gills and live as parasites. As this becomes bothersome for the fish, they eventually dislodge the mussels. The mussels then begin an independent life, choosing their locations in the pond.
Filtering Capacity of Mussels
An adult pond mussel can filter a minimum of 40 liters of water per day. Some sources even claim a filtration rate of 40 liters per hour. However, the filtering capacity is not constant. Mussels are sensitive creatures, adjusting their activity and filtering capacity based on water temperature and other conditions. Mussels need time to adapt to their new environment. Start by introducing a few mussels into the pond, and wait for about a week to observe changes in water quality. If the water becomes clear, you may not need to add more mussels. If the water remains cloudy after a week, consider adding a few more mussels.
Where to Acquire Mussels
Several online shops for pond supplies offer mussels along with fish and pond plants. Ensure that the mussels are delivered in a humane manner. It’s advisable to inquire about the delivery process beforehand. Mussels can sometimes be found in aquarium stores or obtained from fellow pond enthusiasts.
Do not transport mussels with water, as water in a bucket or bag can quickly warm up during the summer. The filtering task can be significant for mussels under unfavorable conditions, leading to the rapid depletion of oxygen, which can be fatal for the mussels. Mussels should be packaged in a bag without water but with oxygen. It’s best to transport the mussels individually to prevent shell-on-shell contact.
Introducing Mussels into the Pond
Mussels require gradual acclimatization. Place the transport bag with the mussels on the water’s surface to allow temperature adjustment. Then place the mussels in a bowl that you can gradually fill with pond water. Finally, set the mussels on a shallow area in the pond. They will find their spot and bury themselves.
Mussels are beneficial pond inhabitants, serving as biological filters. In larger natural ponds, filters may not be required when mussels are present. With mussels in the pond, the water should not be overly clean, and a filter with lower performance is often sufficient. Mussels feed on suspended particles in the water and help counteract algae growth. They do not represent a problem for other pond inhabitants, such as fish and frogs.”