Here's a PDF from the University of Florida aquaculture department. This is a method to treat intestinal nematodes which frequently plague loach species. I also personally recommend a very high protein diet during treatment. Feel free to post comments, questions, or ideas on this thread.
http://edis.ifas.ufl.edu/pdffiles/FA/FA09100.pdf
Excerpt:
http://edis.ifas.ufl.edu/pdffiles/FA/FA09100.pdf
Excerpt:
For intestinal nematode infections of ornamental
fish, several anthelminthics (dewormers) are
available. Two effective and commonly used
dewormers are fenbendazole and levamisole.
Fenbendazole can only be used as a feed additive at
the rate of 1.14 grams per pound of food fed for three
days, with a repeat treatment in two to three weeks.
Levamisole can be used both in the feed and as a bath
treatment. One effective oral dose is 1.8 grams of
levamisole per pound of food fed once a week for
three weeks. One effective bath treatment dose is 2
ppm (mg/liter) levamisole for 24 hours, with a
repeat treatment in two to three weeks. However, be
sure to consult with a fish health specialist before
commencing any treatment and always follow their
recommendations.