I recently read an article that has piqued my interest. It said that many online sources are getting the facts wrong about the identification of those tiny white worms commonly found in fresh water aquariums. The article says that they've been commonly misidentified as planeria worms when in fact, they are nothing more than harmless deritus worms. The differences are as follows:
Deritus worms are, as their name implies, a type of worm that lives off the of the rotten, dead and dieing matter left behind in freshwater aquariums. They are noticeable in one's aquarium when the level of this matter is in excess. They are harmless to aquatic fauna and flora alike, despite being an eyesore to the aquarist.
Planeria worms, on the other hand, is much different, and more severe. They are a species of flatworm, are carnivorous and are very much a threat. They feed off of small fish, fish fry, crustaceans, other small aquatic life. They also feed off of larger fish if they are sick or slow moving and dead or dieing. They can very much be a threat to our aquatic friends. Planeria are usually transferred to aquariums via plants that have come from ponds, as the ponds most likely contain a large number of them already.
An infestation of planeria worms can be treated with either Clout, General Cure, or Jungle Parasite Cure.
I Just wanted to clear things up for everyone.
(Pictures are taken from http://2.bp.blogspot.com/_puTVILFyI9...omposite-2.jpg