The medicated feed I purchased a couple of days ago seems to be helping. The camallanus worms are starting to turn brown, but I still had the concern about newborn worms in the water.
Thanks to a little help from Bob Fenner at Wet Web Media (absolutely THE best online resource for fishkeeping problem-solving), I now have an alternative to levamisole to treat the water. Fenner recommends a substance called praziquantel as an alternative to levamisole, partly because it’s far more accessible.
While I did find an online resource for levamisole at $12 for 17 grams as opposed to the $120 for 5 grams from the local vet pharmacy, the dosing information is sketchy at best, mainly from testimonials posted in different fish forums.
This camallanus worm problem is not one that is very well known. I recall seeing the symptoms, specifically the swollen vent and mucus trails, in the tank my parents kept back in the late 70s. At that time, I had no idea this was a problem and I don’t think much was known about it by anyone outside university research labs. Certainly no treatments were available.
Today’s treatment consisted of an 80% water change and then dosing the tank at the recommended concentration. I’ll do another water change and put the activated carbon back in on friday.