Which Hitch Hiker Do I Have?

[rocknurworld2006]

I have a small tank that i stopped using and is next to the window and there is no filter heater etc on in it, and the water is green obvioucly due to next to window and
there are lots of little tiny things crawling on the glass but im not sure exactly what they are or how they got there, they dont seem to be so much as swimming but just going along the glass and seem to be rounded and come to a thinner body point. there very small and so hard to see so im not sure exatly what they are
its no planaria, or infusoria etc
so question is what do you think it is?
and how did they get in there as was not long ago housed fish

 

[Smells a bit fishy]

Without pics it's hard to say, have a look at the hitchhikers guide, there are loads of them there, and see if any match what yours look like, alternatively post some pics

 

[rocknurworld2006]

to me it looks like cyclops poss?
too small to take any photos of
but how wud cyclops get into a tank that had fish in, as nothing was introduced into the tank
and wasnt there when fish were in it

 

[Caprichoso]

They're probably either cyclops or springtails. They seem to just appear from nowhere lol. I thought they arrived in my tank from the plants I bought and from the bit of water that came with the fish when I netted them and put them in my tank.