The different species feed in three ways, known as the filterers, the graspers and the capturers. The filterers have already been described, their cilia creating currents in the water to bring the food in the region of the mouth. The graspers extend the mastax forward into the mouth, whilst the capturers form a trap by the closure of the corona cilia around the prey. These capturers are always sessile. The species are tremendously varied.
Most rotifers have one eye, some have two and some sessile ones are eyeless.
The bodies of some species have telescopic segments and they can expand or retract like a telescope, whilst others have slight segmentation. Some have a hardened skin, the lorica, and others build themselves a tube to live in. It was reported in the May 1990 Journal of the Worshipful Company of Spectacle Makers that their member Mr. H.J.A. Dartnell was taking part in the 1989-90 Australian National Antarctic Research expedition during which he would be making a study of the rotifers found in Antarctic waters. Dartnell points out rotifers are survivors par-excellence as some species can survive being frozen solid in the Antartic. Also that as there are no fish in the freshwater lakes and ponds of the Antartic there are no predators to eat the rotifers and they therefore proliferate in their billions to such an extent that they colour the water red.