Okay. If people want the facts, here they are. Here are the articles I cited in the article I wrote that was published in this years April issue of Aquarium Fish International on how garlic:
Ankri, S., and D. Mirelman. 2001. “Antimicrobial properties of allicin from garlic.” Microbes and Infection 2:125-129
Boxaspen, K., and J.C. Holm. 1992. “New biocides used against sea lice compared to organo-phosphorous compounds.” European Aquaculture Society
Coppi, A., M. Cabinian, D. Mirelman, and P. Sinnis. 2006. “Antimalarial Activity of Allicin, a Biologically Active Compound from Garlic Cloves.” Antimicrobial Agents and Chemotherapy 5:1731-1737
D.L.N. 1998. “Allicin, one of the active principles of garlic, inhibits the growth of protozoan parasites.” Chemtech 4:45
Holden, C. 1997. “Fighting Parasites With Garlic.” Science. 5338:581
Soko, C. K., and D.E. Barker. 2004. “Efficacy of crushed garlic and lemon juice as bio-product treatments for Ichthyophthirius multifiliis (‘ich’) infections among juvenile Nile tilapia, Oreochromis niloticus.” Aquaculture Association of Canada 9:108-110
And here is my response from a previous thread to that article (mainly its references):
I looked into that article again, especially the references, and was surprised. One of the articles actually states right in the abstract that allicin (chemical in freshly pressed garlic) actually killed ich.
Here are his references and my responses to them:
Colorni, Angelo, Rami Avtalion, Wayne Knibb, Evelyn Berger, Barbara Colorni, & Bracha Timan. 1998. "Histopathology of sea bass (Dicentrarchus labrax) experimentally infected with Mycobacterium marinum and treated with streptomycin and garlic (Allium sativum) extract." Aquaculture 160(1998)1-17.
-This study only shows that Mycobacterium marinum is not cured by allicin. This does not apply to garlic’s anti-parasitic properties since this is a bacteria (or even other bacteria).
Ashdown, Denise & Gary Violetta. 2004. "Using Garlic as an Appetite Stimulant in Sand Tiger Sharks (Carcharias taurus)." Drum & Croaker, January 2004, Volume 35, pages 59-63.
-This study discusses garlic’s use as an appetite stimulant, which doesn’t speak to its anti-parasitic properties (for or against).
Buchmann, K., P. B. Jensen, & K. D. Kruse. 2003. "Effects of Sodium Percarbonate and Garlic Extract on Ichthyophthirius multifiliis Theronts and Tomocysts: In Vitro Experiments." North American Journal of Aquaculture, Volume 65, Number 1, pages 21-24, 2003.
Abstract excerpt:
“Garlic extract had no effect in low amounts (30 mg/L), but at high concentrations (117 and 570 mg/L) it killed the tomocysts within 24 h.”
-This article shows that garlic can actually kill Ich tomocysts, although more garlic is required to be effective compared to malachite green.
Colorni, Angelo & Peter Burgess. 1997. "Cryptocaryon irritans Brown 1951, the cause of 'white spot disease' in marine fish: an update." Aquarium Sciences and Conservation, volume 1, pages 217-238.
-This article’s abstract and introduction did not mention garlic.
Fairfield, Terry. 1996. "Garlic & Your Aquarium: A Preliminary report on Allium sativum and fishkeeping." Aquarium Fish Magazine, January 1996, pages 79-83.
-This is not primary scientific research, and therefore scientifically cannot be considered as proof/disproof or support/lack of support of anything.