Would anyone know what those 1/4 - 1/2 inch long, very thin white wiggle worms in the water could be? I noticed them swimming in a wiggling manner a few weeks ago after I did my water changes of my three tanks. All the fish are healthy with no obvious signs of distress but I'm just concerned about what they are and what health risk they pose to the fish. I can only see them when the aquarium light is on. So they are visible to the naked eye even though they are small and skinny. It's hard to capture them in photos due to their size. I doubt they are tapeworms. Definitely not fish lice or anchor worms. In fact, I don't see any of them attached to the fish but just freely swimming in the water. In any case I dosed the three tanks with prazi powder. The tanks are on the second dose after a break of 6 days after the first dose. But this pesky worms are still there!!! What could they be and how do I get rid of them?