Yo, Albert!
While I agree with you that garlic will most likely not have any great effect on
curing marine ich (and your advise on treating with copper is spot on), I wouldn't be so quick to dismiss the use of garlic entirely. Also, in most of the aquaculture studies that I am aware of the garlic that was used was not fresh, or a derivative was used, including garlic powder. Allicin is not the only compound found in garlic, and much is still unknown in this area, especially regarding marine fish.
http://www.scielo.br/scielo.php?scri...lng=en&nrm=iso
While the document linked to above is a very long read, in the end the authors state:
A. M. Shalaby et al. EFFECTS OF GARLIC (Allium sativum) AND CHLORAMPHENICOL ON GROWTH PERFORMANCE, PHYSIOLOGICAL PARAMETERS AND SURVIVAL OF NILE TILAPIA (Oreochromis niloticus).
Fish Hatchery and Reproductive Physiology Department, Central Laboratory for Aquaculture Research, Abbassa, Abo-Hammad, Sharkia, Egypt
J. Venom. Anim. Toxins incl. Trop. Dis., 2006, 12, 2, p.196
In this particular study the inclusion of garlic at a rate of 3% (via garlic powder) has shown to increase the overall digestibilty of protein, carbohydrates, and fat (ie; better growth), as well as to lower the total bacteria count within the intestine, muscles, and water column.
In Norway, the Austevoll Aquaculture Research Station has studied the use of garlic as a natural biocide against sea lice, with positive results.
http://www.onefish.org/servlet/CDSSe...50cyYzNz1pbmZv
There are other studies that have also shown very positive results in using garlic as a more natural way to control various pathogens.
Effect of Allium sativum on the immunity and survival of Labeo rohita infected with Aeromonas hydrophila
S. Sahu, B. K. Das, B. K. Mishra, J. Pradhan and N. Sarangi
Aquatic Animal Health Division, Central Institute of Freshwater Aquaculture, Kausalyaganga, Bhubaneswar, India
Journal of Applied Ichthyology, Volume 23 Issue 1, Pages 80 - 86
Quote:
Summary
And yet another study .........
EFFECT OF GARLIC ON THE SURVIVAL, GROWTH, RESISTANCE AND QUALITY OF OREOCHROMIS NILOTICUS
Salah Mesalhy Aly, Nashwa Mahmoud Abdel Atti* and Mohamed Fathi Mohamed
The WorldFish Center, Research Center for Africa & West Asia, Abbassa, Sharkia, Egypt.
Dept of Food Hygiene, Animal Health Research Institute, Ismailia Laboratory, Egypt.
http://ag.arizona.edu/azaqua/ista/IS...%20Meselhy.pdf
In Israel, researchers from the Ben Gurion University aquaculture dept. are also experimenting with allicen, the active ingredient in garlic, for its anti-bacterial properties.
http://www.foodengineeringmag.com/Ar...100000f932a8c0
Hope all is well in Van!
Neil