In your first post you said you completely emptied your whole tank and cleaned it. You should never do this. This means your tank had to cycle all over again with a lot of fish in it. Do you have a water
test kit? You probably have very high
ammonia levels especially with so many fish in an uncycled tank. The planaria you were trying to remove are gross but harmless. I have them in one of my tanks and removed them by simply wiping the inside of the tank with a piece of filter fiber (it looks like a big bag of cotton and it's cheap). Also vacumning the gravel after wiping the sides helps.
I would get a water test kit and post your results here. People here can instruct you what to do after seeing your readings. You need to do this quickly or you may lose all your fish.