Torches are notorious for getting bacterial infections. Look up brown jelly disease. How long have you had them? Lots of them are coming from the wild and come in stressed and start showing issues a month or so down the line. Usually once they are in our tanks for a few weeks. There has been some recent information on treating your whole tank with antibiotics to get rid of the bacteria Acrobacter that causes the torch issues. There are test that can be done to test for it but its like $100 each.