On 2016 Jan 04, S A Ostroumov commented:
Rotifers: Rotifers are an important part of the freshwater zooplankton, being a major foodsource and with many species also contributing to the decomposition of soil organic matter. Most rotifers are around 0.1–0.5 mm long, and are common in freshwater environments throughout the world. The word "rotifer" is derived from a Latin word meaning "wheel-bearer", due to the corona around the mouth that in concerted sequential motion resembles a wheel (though the organ does not actually rotate). The coronal cilia create a current that sweeps food into the mouth. Rotifers eat particulate organic detritus, dead bacteria, algae, and protozoans. They eat particles up to 10 micrometres in size. Like crustaceans, rotifers contribute to nutrient recycling. For this reason, they are used in fish tanks to help clean the water, to prevent clouds of waste matter.(Wikipedia was used).
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