are there parasites in my fish tank?

[Craig]

i was just doing my regular tank cleaning and i noticed these little hair looking things in it. i thought maybe it really was hair. but then they started wigling really fast and moving throughout the tank.
so i kept watching these hair like things and i think its some sort of parasite maybe?
they vary in length from very small to about half an inch long.

very thin and white in color. what are they?? and how do i get rid of them?

[catx]

Sounds like planaria or nematodes. Harmless generally towards fish - and may well get munched by them. An overload of these is a sign there's too much decaying matter in your tank. Make sure you're doing regular partial water changes and gravel vacs.

The only time I've had these appear was when a snail died. They disappeared after a water change or two. They're always in the tank, but usually in such small numbers you won't see them.