I believe that I have vorticella in my 5 gallon Neocaridina tank. I have noticed it only on the plants and not the animals, so I have removed as many floating plants, etc. where I could see it. Since discovering it, I have also taken out the 3 snails that were in there. In researching, I decided to go with API's Pimafix for one week, and thus also added an extra sponge filter for aeration. The current inhabitants are 9 shrimp and 4 zebra danio fry. Have you had any luck with eradicating vorticella? My guess is that it came in on one of the shrimp (one recently died), as I do weekly 25% water changes, so I don't think this is from a dirty tank. Any advice is appreciated, however, I am not willing to treat with something that can potentially kill the shrimp.