Camallanus Worms

Question
I have a 10g tanks that is currently the home to 3 guppies and one platy as well as about 30 baby guppies (most about to go to a new home).  We have been feeding the adults an antiparasitic food that contains .4% levamisole  in order to get rid of an infestation of camallanus worms.  We have given it to them for 4 weeks now with 3 days on, 4 days off as per the instructions but it doesn't seem to be having any affect on them.  What am I doing wrong?  we ave already lost one fish to the darn things and three others are showing worms now.  I don't know where I can get the straight Levamisole in western Canada and wonder if that would make a difference.  Should I feed it to them constantly (Possible constipation issues?)? and see if it makes a difference?  I don't want to lose any more fish but I am concerned.

Thanks in advance for your help.

Jenn

Answer
Jenn,
these are nasty parasites indeed.
this is what I found that will work if you can get it.
Fenbendazole.
Dissolve 3CC of powdered Fenbendazole in 100ml of water.
Mix well, then add as many bloodworms as you need to feed your fish. Soak for 30 mins to 1 hour, then dump the entire container in the tank, water and all.
The brand name it goes under is Panacur. It usually comes as a powder, or pill if the latter you can simply crush it.
Lets give this a try and see how it goes.
Let me know.