[CoreyH]

Hello!
Okay so, today I observed my poor aquascaping skills and considered rearranging my plants.
Leaf pruning went well, and so did the root snipping. After the taller plants were removed, I pulled up my microswords. When I went to check the roots, "ooh thats just a big bright red fish poo tangled in the roots...wait, there are no large fish in the tank.. (I touch it...it moves... I freak )

Therefore, I quarantined the plant and this 2 inch worm. I've never seen a worm like this. I am aware of the differences between blackworms, tubifex, and bloodworms, so this little guy is special. When I dumped it into a small dish, the worm contracted and flattened. Later after noticing its attempt to squirm out, I noticed that it also clings to objects unlike other worms its color resembles. First thing that came to mind was: "oh no! killer leeech!" APC members, please help me determine the species of this worm and whether it is a species beneficial to my tank or a monster that will destroy everything.

I've provided two photos of this death machine.

 

[HeyPK]

It looks like an aquatic annelid oligochaete, probably closely related to earthworms. It is an innocent consumer of detritus, not one of the "Monsters Within Us" sensationalized on Animal Planet.

 

[CoreyH]

Thanks alot HeyPK. I am relieved.

 

[Newt]

That'd be fish food special treat in my tank

 

[miremonster]

Hi CoreyH,

years ago I've found worms like that in my tank, between plant roots. They matched Your description and pics. A zoologist from Humboldt University, Berlin, told me that it is a nemertine worm ( http://en.wikipedia.org/wiki/Nemertea ) but couldn't ID the genus and species. Most Nemertines are marine, only few freshwater species. I guess it was Apatronemertes albimaculosa, this species was described first from specimens found between Vallisneria roots in an aquarium in Germany.
http://books.google.de/books?id=GqI...CFwQ6AEwCA#v=onepage&q=apatronemertes&f=false

 

[Jeffww]

I have those worms too. I take special care not to hurt them when I root around in the substrate. Worms are good on land in underwater.

 

[Treetom]

I just redid my ten gallon to set up sand/kitty litter Cherry shrimp tank and found one of these in my bucket. It moves like a leech, extends way out, attaches, shrinks way up to about 1/8 it's size and so on. I put it in my community tank in hopes the bigger fish would eat it... Nope... It swam like an eel to the bottom and dug in super fast. Glad to hear I'm not breeding leeches.

 

[HeyPK]

It certainly sounds like a leech. Maybe you will be breeding them!