- Nematodes, or roundworms, are part of the phylum Nematoda which is one of the most diverse phyla and it has been argued that the phylum should be split into different groups.
- Nematodes are extremely hard to distinguish and there are about 28,000 species that have been clearly identified and 16,000 of them are parasitic
- There are a total of about 1 million species of of nematodes
Nematodes have adapted to almost every fresh water habitat and other habitats as well.