Muskrat Holes and Duckweed Control in Farm Ponds

Identifying the Burrower

Holes 1–2 inches in diameter angled into the bank of a 30×50-foot pond are classic muskrat dens. Muskrats are nocturnal rodents that burrow into earthen banks. Crayfish chimneys, by contrast, are smaller (≈1 inch) with muddy mounds around the entrance. Neither poses a structural threat to a dirt-bottomed pond, though muskrats may nibble aquatic plants.

Living with Muskrats

Trapping is an option, but many pond owners prefer coexistence. Muskrats are part of the ecosystem and rarely cause catastrophic damage.

Natural Duckweed Management

Herbicides like Weedtrine and Cutrine offer only temporary brown-out; duckweed returns within weeks because the nutrients remain. Instead, address the root cause:

• Add consumers: Goldfish, koi, grass carp, turtles, ducks, and even muskrats eat duckweed.
• Increase water movement: Duckweed hates current. Install an aerator, fountain, or diffuser to disrupt the surface.
• Physical removal: Regular skimming reduces the population.
• Nutrient reduction: Limit fertilizer runoff, remove decaying leaves, and add competitive plants like water lilies and submerged oxygenators.

Benefits of Aeration

Aeration not only discourages duckweed but also raises dissolved oxygen, supports beneficial bacteria, and creates a healthier pond overall.