Fly Fishing Techniques

While I was giving fish medicine for white spots, I saw maybe 10 worms on the upper glass of the aquarium… For now I just wiped them and threw them in the garbage but I am sure there is much more…
Any idea what are these worms? How can I fix this problem? From where did they come from..?
Note: They are small and white and i found some in the water… I also saw that there are small flies around the aquarium…
Thanks!