well i'd guess fire is the next step?? lol
dang, if a good dose of pp didn't do it, i would tear it down and bleach it. and speed up the water changes, and wipe down the walls more often. i hate them wormy looking things. i have never seen one on the fish, just on the glass. i wonder if they inhabit the sponge? lots of people microwave sponges to kill nasties. hth cg