What Are the Benefits of Gravel in Fish Ponds?

Gravel has many benefits in a fish pond. Rocks and gravel are important for a healthy ecosystem and extend the life of your pond liner.

  1. Function

    • Gravel is placed in the bottom of a fish pond to cover the pond liner, similar to covering the bottom of a fish tank with gravel. Typically ponds owners line their ponds with large gravel and rocks.

    Uses

    • Gravel- and rock-lined ponds protect the pond liner from UV rays which deteriorate the pond liner and add weight to prevent the pond liner from shifting. Gravel and rocks add a decorative element to fish pond setups.

    Benefits

    • Fish pond bottoms become covered with sludge that forms from fish waste, and dead and decaying material. Rocks and gravel provide a surface for bacteria to grow that will eat away the sludge and prevent it from polluting the pond water.

    Significance

    • The bacteria that grow on the gravel are the same bacteria that grow in a pond filter. A gravel layer will make cleaning the fish pond easier since it removes much of the sludge the same way a pond filter removes toxins.

    Theories/Speculation

    • Water gardeners and koi pond keepers debate whether gravel-lined ponds are beneficial. While many people believe gravel and rock have beneficial qualities, some people believe that gravel will form a stagnant water zone at the bottom of the pond full of rotting waste, where clean, moving water cannot reach to flush it out.