Although commonly referred to as “worms”, microworms, banana worms, and walter worms are actually different species of harmless nematodes. The main difference between them is size and they are all cultured the same way. They are all very tiny, but they differ slightly in that banana worms are the smallest, walter worms are the intermediate, and microworms are the biggest (all less than 3mm full grown).
They are the perfect live food for many types of nano fish, baby axolotls, and fish fry. When added to water, they sink to the bottom and can survive for up to 24 hours, making them especially ideal fry food for almost all species of fish. They are also very easy to culture and maintain so long as one remembers to re-culture them every few weeks.