Food consists of living organisms especially bacteria, 2 to 5 millions of bacteria are devoured in 24 hours by a single Paramecium. It also feeds upon other small Protozoa, unicellular plants (algae, diatoms, yeasts etc.) and small bits of animals and vegetables. In a sense, paramecia render a useful service to bacteria lest they might reproduce or multiply too rapidly to endanger their own existence by crowding. Paramecium is a selective feeder showing considerable choice of food and often rejecting indigestible non-nutritive particles.
Paramecium is not a carnivore or predatory type. It feeds in a holozoic manner, not like Amoeba, but by ciliary action. It feeds while stationary or browse when swimming slowly, and not when swimming fast, while feeding, the cilia of oral groove beat more strongly than the body cilia, causing a vortex or feeding cone of water to form. Thus, food particles are sucked with the water current into the oral groove and then flow to the vestibule. Ciliary tracts of vestibule direct the food particles into the buckle cavity where food is ingested.
Paramecium is not a carnivore or predatory type. It feeds in a holozoic manner, not like Amoeba, but by ciliary action. It feeds while stationary or browse when swimming slowly, and not when swimming fast, while feeding, the cilia of oral groove beat more strongly than the body cilia, causing a vortex or feeding cone of water to form. Thus, food particles are sucked with the water current into the oral groove and then flow to the vestibule. Ciliary tracts of vestibule direct the food particles into the buckle cavity where food is ingested.