Agreed, Levamisole is the med of choice, but not at the dosage rate stated in the link posted above.
........
http://www.loaches.com/Members/shari2/levamisole-hydrochloride-1
It appears that the scientific community considers 2ppm of Levamisole HCl to be an adequate dosage, which works out to 1gr per 100 gallons,
not 5gr per 100 gallons as constantly reported on the internet.
The 5gr dosage rate originates from Charles Harrison, who is a chemist/ fish hobbyist, that sells Levamisole HCl, not a VMD that specializes in treating tropical fish. (such as Dr. Roy Yanong)
http://fishweb.ifas.ufl.edu/Yanong/Yanong.htm
Dr. Yanong also suggests that the treatment duration be 24 hrs, not 3 days as currently suggested by Charles Harrison. .....
Good luck.