As an obligate carnivore, the common kingfisher's diet is overwhelmingly piscivorous, though they opportunistically consume other aquatic organisms. Their primary prey includes:
- Small fish (such as minnows, sticklebacks, and roach)
- Freshwater shrimp and crustaceans
- Tadpoles
- Aquatic insects and their larvae (e.g., water beetles)
The kingfisher is an ambush predator, typically hunting from a fixed perch extending over the water. It sits motionless, its keen eyes scanning the water below. Once prey is sighted, the bird bobs its head to accurately gauge the depth and trajectory, compensating for the water's refraction.
It then launches itself into a steep dive, entering the water with its beak slightly open. Grabbing the fish firmly, the bird immediately uses its short wings to power back to the surface and return to its perch. Before swallowing its catch, the kingfisher engages in a brutal processing technique: it repeatedly and violently beats the fish against the branch to stun or kill it and to break its internal spines. The fish is then manipulated and swallowed headfirst to ensure the scales and fins slide smoothly down the bird's throat.