What is this flat slug/worm thing in my aquarium?

[NoMoreGoldFish]

I came home tonight, turned the light on and saw it on the glass. It doesn't crawl, but stretches out pretty long and then pulls its body up to move. It's about an inch long when it stretches out. It's not planaria as it doesn't have the squid shaped head and it moves about differently.

Could it be some kind of larvae?

 

[NoMoreGoldFish]

Nevermind, it's a leech. How did it get in my aquarium? The last time I bought a plant was two weeks ago.

Anyway, are they harmful? Should I put the little guy back in?

 

[librarygirl]

I don't know if it is but I don't think I could sleep with that in my tank. LOL

 

[Homer8]

that thing is giving me the creeps. if you are thinking of keeping it atleast put it in water to keep it alive until you find out what it is.

 

[mfdrookie516]

flatworm - FAQs on Freshwater Flatworms (e.g. Genus Planaria)