Weird white (parasite?) thing.

[HoochieCoochieMan]

I just woke up and turned on my tank and I see what I think is crap just floating around but it's white and it's swimming up towards the light. I also see smaller versions of it. I'm kind of nervous, I've not added anything (fish, plants, or new foods) in months, and I did the monthly 50% water change the other day. The only problem I have with the tank before this thing is a slight algae problem.

I don't see it -on- my fish, so it's not external. Or it's in an intermediate in its life.

If I could get advice on what it is and if it might be harmful, as well as treatments, that would be great.

 

[HoochieCoochieMan]

Oh wait, I did add an additional filter the other day. Wanted to transition to a stronger one from the stock one that came with the kit. But I rinsed it and everything thoroughly.

 

[Lupin]

Possibly planaria? Though it's not that harmful so I wouldn't worry about it if it is. Parasitic worms usually do not leave their hosts unless they were already killed by anthelmintics thus are purged out of their hosts' bodies.