What does common carp eat?

The interesting thing about carp feeding is not what goes into the mouth but what comes back out of it.

A carp takes in a mouthful of silt and organic matter, sorts it internally, and expels what it does not want through the gills and the mouth. The sorting is precise enough to separate a single food item from a mouthful of debris, and it happens fast enough to be effectively continuous while the fish works over the bed.

Both verified relationships describe what survives that sorting: aquatic insect larvae, dominated by chironomid larvae in silt, and molluscs — snails and small bivalves crushed with pharyngeal teeth in the throat.

The sensory arrangement supports it. Taste and smell dominate, and carp carry taste receptors not only in the mouth but across the barbels, the lips and parts of the body surface, so the fish is tasting the sediment before it is in the mouth at all.

The consequence that matters for the animal is that a carp is an efficient exploiter of productive sediment and needs no visual acuity to be one. The consequence that matters for angling is set out separately below, and it is the clearest case in this catalogue of a feeding mechanism driving a piece of tackle design rather than the reverse.

Feeding is strongly temperature-linked, and in cold water it slows to very little, which is why the fishery is a warm-season one across most of the range.

The sorting mechanism is the reason a whole branch of terminal tackle exists. A carp that can separate one item from a mouthful can also detect that one item is tethered differently from the free offerings around it, and eject it before an angler knows anything happened. The hair arrangement — presenting the offering separately from the hook — was developed as a direct response to that, and it is one of the few places in this catalogue where a piece of angling design can be traced to a specific piece of feeding physiology.

The chemosensory profile is the reasoning behind soluble attractors, oils and amino acids in carp baits, and it is practitioner consensus of great depth and very little controlled evidence.

One welfare consequence is not interpretation: carp are long-lived, frequently caught repeatedly, and handled more than almost any other fish in Europe. Unhooking mats, wet hands and minimal air exposure are the standard, and the specialist bodies are explicit about it.

Both relationships are group-level, and a carp's diet includes a large plant and detritus component that no relationship represents. In heavily fished waters, angler-introduced food forms a substantial part of what carp eat, which is not a natural diet fact and is not modelled here. Nothing establishes proportions.