From The Aquarium Wiki You can contribute to the Aquarium Wiki
by expanding this article. Dont be shy!. What is it A nematode
is a micro sized worm often called roundworm (they are roughly
2-5mm long). There are over 20,000 species of them. and they
provide an important service in ponds, lakes, etc. They live in
all habitats, and most are aquatic. They generally are only a
few mm in length and have a life-cycle of a few days. - Some
species are parasitic and live off fish, often appearing in the
anus of the fish. But by far the majority are harmless.
Aquarists often first come across these harmless 'white worms'
when they spot them in their hundreds massing on the sides of
the aquarium in newly set up aquariums during the cycle process,
when the aquarium is lacking in oxygen or if the tank is heated.
They help to break down organic matter (mulm) and some fish like
small gouramis are know to eat them. If you've added something
organic (wood, other fish,raw fish food,etc.) to the tank you
can easily introduce t