Ducks are opportunistic omnivores, but whether they eat bass depends on the duck species and the size of the fish. Only a few specialized duck species consume fish, and if they target bass, it will only be the smallest, most vulnerable juveniles. The vast majority of ducks are not equipped to hunt or swallow a mature bass, which remains safe from avian predation. This predatory behavior is limited to a small group of highly adapted waterfowl.
The General Duck Diet
Most common ducks, such as Mallards and Northern Pintails, are classified as “dabblers” and rely primarily on plant matter and small invertebrates. These species typically feed by tipping their bodies forward in shallow water to reach submerged aquatic vegetation, seeds, and roots. Their wide, flat bills are structured with fine, comb-like serrations, called lamellae, which are optimized for filtering tiny food particles from the water or sifting through mud.
The animal protein in a dabbling duck’s diet usually comes from aquatic insects, larvae, snails, and small crustaceans. These small prey items are readily available in the shallow water habitats where dabblers spend most of their time. This reliance on filtering and grazing means that larger, faster prey like fish are not a regular part of their feeding strategy.
Duck Species That Hunt Fish
A distinct group of waterfowl, known as diving ducks, have specialized adaptations allowing them to hunt and consume fish. The most prominent examples are the highly piscivorous Mergansers (Common, Red-breasted, and Hooded). Unlike dabblers, these ducks possess a sleek body shape and powerful legs set far back, providing propulsion for underwater pursuit.
Mergansers are easily identified by their narrow, pointed bills, which differ from the broad bills of dabbling species. These specialized bills feature sharp, backward-pointing serrations along the edges, giving them an efficient, vice-like grip on slippery prey. This allows them to firmly hold small fish while swimming underwater and during the journey back to the surface. Diving species have denser bones and can compress their plumage to expel air, reducing buoyancy for efficient underwater swimming.
Size Constraints and Prey Selection
Even for specialized fish-eating ducks, there are strict constraints on prey size. A mature adult bass is too large, robust, and heavy for any duck to capture or swallow whole. The size of fish a merganser can handle is typically limited to a few inches in length, generally under three to five inches.
If a piscivorous duck consumes bass, it will exclusively be juvenile fish, such as fry or fingerlings. These small bass are caught opportunistically alongside other schooling fish like minnows, shiners, or perch. The hunting method involves pursuit diving, where the duck actively swims after the fish, relying on speed and its serrated bill to secure the catch.