Planaria or nematode?

[hb3133]

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Upon close inspection of my newly planted 10 gallon tank, I notice these small, 1/32 inch or so, moving objects. They are tanish/white color and are about the diameter of a human hair. They seem to move by inching their bodies around. I only see them on the bogwood. Any help would be greatly appreciated?

 

[kveeti]

Planaria crawl on surfaces.
Nematodes swim frantically in an S-shape in the water.

 

[plah831]

I agree that it sounds like a flatworm of some sort, from the way it moves.

I have found things like you're describing crawling around in gravel in freshwater tanks. I was worried that they might be internal parasites that were coming out in the fish feces (like tapeworm in dogs), so I rushed a fish to the LFS. Once there, I saw the same phenomenon in their tanks, and the girl there told me it was just commensal critters (meaning they won't affect the fish one way or the other), probably feeding off nutrients and stray food in the substrate. I hope it's the same situation for you.