The Virginia opossum, Didelphis virginiana, is the only marsupial found in North America and is a familiar sight in many backyards. These adaptable creatures are often seen foraging at night, leading many pond owners to wonder if their aquatic inhabitants are at risk. This article explores the dietary habits and behaviors of the Virginia opossum to determine their likelihood of preying on pond fish.
Understanding the Opossum Diet
Opossums are opportunistic omnivores, with a highly varied diet. Their natural diet primarily consists of insects, such as grasshoppers, crickets, and beetles, along with carrion (dead animal matter). They also consume a wide range of plant-based foods, including fruits, grains, nuts, and seeds. This adaptability allows them to thrive in diverse habitats, from forests to urban areas.
In addition to plant and insect matter, opossums consume small animals like mice, rats, voles, young birds, snakes, frogs, and crayfish. While fish are a possible food source, they are not a primary prey item. Opossums are more inclined to scavenge for food, meaning they will eat fish if they are already dead, dying, or easily accessible in very shallow water.
Opossums and Water Environments
Opossums are proficient swimmers, employing a “dog paddle” style and using their tail for steering. They can even dive underwater for short periods, often to escape predators. Despite their swimming capabilities, opossums generally prefer to stay on dry land, as their fur is not naturally waterproof and prolonged water exposure can cause their body temperature to drop.
These animals typically enter water only when necessary, such as to cross a barrier, evade a threat, or reach a food source. If an opossum is found near a pond, it is more likely seeking water for drinking or foraging for insects, snails, or vegetation along the water’s edge. While they might investigate a pond, their slow movement and lack of aquatic hunting adaptations make active predation on healthy, swimming fish highly improbable.
Protecting Your Pond
Given that opossums are not significant predators of pond fish, protective measures often focus on deterring a wider range of opportunistic wildlife. Secure food attractants by keeping pet food indoors, ensuring garbage cans have tight-fitting lids, and managing compost piles. Removing easy food sources reduces the likelihood of scavengers, including opossums, lingering near your pond.
Physical barriers offer effective protection for your pond’s inhabitants. Pond netting can be stretched over the water to prevent animals from accessing fish, while fencing around the pond area can deter larger terrestrial predators. Additionally, designing your pond with deep sections (at least three feet deep for fish like Koi) and providing ample hiding spots, such as underwater vegetation or rock caves, allows fish to escape potential threats. Using motion-activated sprinklers or lights can also startle and deter nocturnal visitors.