A paramecium is a small one celled (unicellular) living organism that can move, digest food, and reproduce. They belong to the kingdom of Protista, which is a group (family) of similar living micro-organisms.Micro-organism means they are a very small living cell.he paramecium is an oval, slipper shaped micro-organism, rounded at the front/top and pointed at the back/bottom. The pellicle, a stiff but elastic membrane that gives the paramecium a definite shape but allows some small changes.