Hello, I have a 29 gal freshwater tank with mostly Rainbows. I noticed tiny white caterpillar-like critters on the inside of the tank glass about 2 months ago. I told a local fish store about them and they said that since they didn't appear to be on the fish, it was probably nothing to worry about. Well since then I've had 3 fish die and the tank glass seems infested with these things. They are barely big enough to see with the eye, look like a thin white worm and if you watch them long enough they obviously move and crawl across the glass. I believe I had them once before about 10+ years ago and I thought they were called "flukes" or "tank lice". I have tried quick-cure with no effect. I also tried coppersafe and that doesn't seem to be working either. If anyone has any experience with these or can at least identify these things, please let me know. Thanks in advance for any info offered!!