Rotifers are more complex than protozoan (classified as metazoan) and exist in a wide range of shapes and sizes. The taxonomic classification of rotifers is currently in flux, however it is generally accepted that over 2,000 species of rotifers exist.
The majority or rotifers are motile and may also attach to flocs. Rotifers feed on small particulate matter such as dead bacteria, protozoan, and other particulate organic material. In practical experience, we have cited the presence of rotifers in SRT values of three to four days, so therefore it is not considered good practice to attempt to correlate rotifers with SRT
