tiny white wormsin tank and tiny white tadpole like swimmers

Question
I have looked them up, and supposedly they are flatworm or some weird parasite, will they kil my fish and are they harmful to children, adult or pregnant women, we do not play in the tank just wondering if they can harm us, basically asking is it better to let be or get rid of the tank??

Answer
Hi Princess
Well, generally if you see a worm or critter swimming around, and it's not attached to the fish, they're usually going to be harmless to the fish then.  They're most likely scavengers.  And ditto for humans.  I would still wash my hands after doing a water change or having your hands in the tank though.  But they won't hurt you.  

Tiny white worms....the most common ones, in my opinion anyway, are thin like a hair, usually whitish colored, usually hanging out in the gravel until you do a water change-then they start swimming all over the place, and when they swim they swim in an S shape-those are nematodes.  You'll see them in planted tanks-usually hitching a ride on a plant, or even when you buy a fish-they can be in the water.  They help eat the waste that's leftover in the gravel, so not really bad.  But, if the tank isn't cleaned regularly(weekly), they're numbers can bloom and then you can run into some water quality issues.  Best bet to keep them under control, do regular weekly water changes/gravel vacuums of at least 25%, and don't overfeed the fish.

Now the other more common worm type thing seen in tanks, is called planaria.  They basically look like a white/grey colored slug(snail with no shell), usually you'll see them hanging on the glass or crawling on the gravel, and they have an arrow shaped head.  These guys are also harmless to fish and humans, but some species do like to eat fish eggs and small fry.

The tiny white tadpole things....that one has me stumped. Only thing that really comes to mind is mosquito larvae.  They kinda look like a tadpole I guess, but I would say more like a worm.  They'll mainly hang towards the surface.  Another possibility is a cyclops.  It's very tiny though, like little specks, so I don't think that's what you're seeing.  Here's a link I have-unfortunately I lost some of my good ones with good pics, but there's photos as well for all those I mentioned on there:

http://www.planetinverts.com/what_is_that_bug_in_my_aquarium.html

Hope that helps and let me know if you have more questions.

Christy