Muskrats dig burrows typically at the water’s edge.  The burrows often collapse causing shoreline erosion and sink holes. This can be a hazard to people, pets, livestock or other wildlife for foot or leg injuries. It can also be a problem mowing grass with lawnmowers or equipment around ponds as equipment can become stuck when a burrows collapse. Muskrats eat vegetation and there can be considerable damage to your emergent aquatic vegetation. They are in the rodent family and do cause chew damage on pond equipment cables.

​Beavers may build damns to purposely raise water levels so they can create suitable habitat for themselves. The damns can cause excessive flooding problems. Beavers cause severe damage to trees including dropping them to the ground. A pair of beavers can kill and level dozens of trees around a water body.

Mink and Otter eat fish and are excellent swimmers.  Either of these species can take a large number of fish out of your pond and also have a negative impact on some species in lakes. Both are rarely seen as they are most active at dusk until dawn.