Ok so this isn't my betta tank, but in my cold water WCMM tank..
I know I've been a tad bit .. well I'm used to my Comet so I've been over feeding a bit (stupid baby fishies) and I haven't been able to gravel vac as much as I'd like (stupid baby fishies!) and I put my plants into a big plastic white bowl and when I moved them back into the tank after a short rinse in tap water in the bowl I noticed 2 worm things.. They are not free floating swimming wiggly things like I've seen online pictures of, but they're like leeches.. flat and they move like worms (stretch out.. shrink..) and they can move pretty fast too. I know they're flat and white in color. They are only on flat surfaces, like glass, the bottom of the bowl, etc
Sorry I couldn't get a picture, since they were white in a white bowl. I never see them in the tank, only in the bowl I use for my water changes. I now have the babies in a net breeder so I can gravel vac and feed them easier and so I can feed the adults about 10 tropical fish pellets. I have 4 ghost shrimp but I guess they're not cleaning up extra food like I hoped. Well they are, but I wish they had bigger stomachs.
So.. other than gravel vac, less food etc, do you think there is a treatment for these guys? I do have a snail and could easily put him in my old 2.5 that I fixed up QT tank and put something in the water? My fish do NOT eat these.. they don't even eat their own fry :( I have standard aquarium salt and maybe some epsom salt if that'd help. I haven't salted the tank since I got my snail. I used to do a small pinch for my 10 gallon in the filter to dissolve.