About a week ago I noticed these tiny, threadlke things floating in the water of my aquarium and on the surface. I'd been doing 25% water changes every two days because of a fin-nipping betta already. The things very quickly mulitplied, and i've done two 50% water changes in the last week. I did one yesterday, and there weren't many of the things left, but I look at my tank this morning and the population has skyrocketed again. I haven't added any new fish or plants recently. The temperature of the tank is 82 degrees, and it's a filtered, cycled 10 gallon. The only things I add to the water are conditioner, a live plant supplement, and salt, to help the betta's fins heal. I feed freeze-dried bloodworms and flakes. What are these things, and how do I get rid of them? Are they some kind of algae, or worms/a parasite?? The fish seem to be acting normal.