CichlidFish.com - Fish That Think.

After I clean the gravel in the tank with fifteen discus (fed with tetra discus), in the buckets with the siphoned out water I can see millions of thread like, really thin, one-inch-long white worms . They sort of try to swim in there, zigzaging in one place very inefficiently, not getting anywhere. I cannot see them in the tank. I don't know how long I've had them for. A friend noticed them when helping me with the buckets. The discus seem to be fine, eat like hell. Since I discovered them for the first time some 2 weeks ago I have been cleaning the gravel weekly, changing some 40% of the water in the process. The worms are still there and it appears that their amount isn't even diminishing.

I don't mind the worms. Even if not exactly pets they don't swim around in the tank, and, perhaps help with the processing of leftovers and feces. In that case I don't really see a point in getting rid of them.

However, I am afraid they could be parasites. As I said the discus have been sharing the tank with them for at least two weeks and seem perfectly healthy. But could it possibly be that it would take longer for the problems to show?

I do not have a photo right now but will take one next time I clean.

What do you think? Could they possibly be parasites?

Hard to say exactly just from a description. Probably not parasites. More likely planaria or something, feeding on waste and decaying food. I'd suggest just keeping up on your water changes and filter cleanings, and do some regular gravel vacuuming. Also be careful of overfeeding. Try not to give your fish more than they'll eat in 3-5 minutes or so. Should clear up.