It sounds like your fish are in the beggining stages of an ich brake out and if you dont know the parisite i will tell you what it is. Ich is a parisite that your fish will get when water quality is decreasing or your fish are in a lot of stress, the begging stages is when the fish is rubbing wich means the fish is trying to rub the parasite off, as it gets worse you will see white spots on the fish wich is the parasite wich accually will dig its head into the fish and slowly start eating the fish, the place where you see ich the most is around the gills where. You will start to see more and more white spots as the ich gets worse, this parisite will spread rather quickly and just over night you could have up to 500 to 1000 of these little paristes in your tank and this pariste is highly contages and will attach to any fish in its path. This probably one of the worse parisites to have in your tank. You can get rid of it buy puchesing a good medicine good meaning dont go with tetra or cheap brands like that, get a liquid form medicine that has copper sulfate as this will last up to a month and kill off the ich rather quickly and if this dosnt work right off get somthing a little more strong. And if one of the ich spots fall off dont be fulled because they can become active again buy another ich parisite bonding with and reviving it and then they both will be active again so keep a close eye out for it even if they look clear as you should watch your fish closley every day. Also check your water quality and make sure every thing is near good, hope this helped and if you need any more information just ask or go to my page and right your question there hope the ich gets cured.
You will know by the amount of ich on the fish, if it is extreme, meaning that the fish looks like it has been power blasted with salt than it will be prety hard to heal the fish and will most likly die. If the fish has a few spots meaning 3 to 5 spots than it will be eiser to heal and can have a good chance of living. Like Ashley h. said above do 10 to 15 percent water changes in between doses meaning gravel vacuming to get the ich that may have fallen of the fish and settled in the gravel or sand and by doing the water changes you can get these out. Hope i helped again and feel free to ask questions on my home page.