Rotifers are tiny, aquatic animals that belong to the phylum Rotifera. They are typically less than 1 millimeter in size and can be found in freshwater, saltwater, and moist environments. Rotifers have a unique structure called a corona, which consists of cilia that help them move and feed by creating water currents. These organisms play an important role in aquatic ecosystems as they feed on microscopic algae and bacteria, helping to maintain water quality. Rotifers reproduce both sexually and asexually, with some species capable of producing resistant eggs that can survive harsh conditions, ensuring their survival in various environments.