What are the worms in my fish tank and how do I get rid of them?

these are nothing to worry about just cut down on feeding and increase the water temp to 80 degrees for about a week the fish can and willeat the worms and its fine they are harmless its just from overfeeding the increased temp for a week kills them off and cutting down on the food will make sure they stay gone thats how they got there in the first place

sounds like planaria ... possibly you are feeding your fish too much as this can lead to these worms in your tank ... they will not hurt your fish but will eat fish eggs so if you are doing any breeding it is not a good situation ... you are going to have to clean your gravel really well, cut down on how much you feed the fish and i think you can add aquarium salt but you would have to google that for the amount needed for your tank :O)