treating for worms

[cichlid2006]

ok ive been treating for worms, callamanus. im using a discus preperation of 50mg/g flubendazole. some of my fish seem to be getting better and are beginning to poo normally. but a few of them dont seem to be getting rid of the wroms and its beginning to trouble me.
can a callamanus infestation be so large that its better to eithanise the worst affected after treatment appears to have done very little or nothing??
i will be carrying on treatment for a few more weeks to ensure erradication but im wondering if erradication will go quicker and be safer for the others if i euthanise the most infested fish?

 

[Lupin]

If flubendazole doesn't help, isolate the ones hit worst and try levamisole hydrochloride. Smear their foods with garlic to encourage them to eat.

 

[cichlid2006]

they are eating garlic cloves and i soaked bloodworm in the fluben mix before adding to the aquarium to ensure everyone had some fluben ingested to target the worms better.
ive asked the local vets for levamisole hydrochloride to price it up just in case but they say they dont stock it and wont be either as they have no call for it. so im at a loss of where to get some.