There has been quite a lot of discussion about garlic, both questioning its benefits and also raising some evidence that it may damage the livers of SW fish. Here's a link to a good thread here on RC:
http://reefcentral.com/forums/showthread.php?p=12393383&highlight=liver#post12393383
Thanks for posting the link, I'll take a look at it later tonight. Many medications can damage the liver. Bacterial infections can also target the liver, as well as fatty liver disease. It's enough to drive fish to drink
For the record, I have never made it a practice of using garlic as a treatment for disease. As it turned out, one of the flake foods I bought from OSI contains garlic, as well as the Ocean Nutrition nori I picked up. Seeing "contains garlic" on the container isn't a pro or con for me. I have always considered the practice of dosing garlic as a chicken soup treatment.
My official stance on the matter of quarantine is to prophylactically treat all fish with a cocktail of antibiotics, copper, quinine, hyposalinity and the use of oxidizing agents. I has a wholesale tropical fish importing business for 8 years with 30,000 gallons of holding tanks. Medicating fish is the only way to assure good health (along with good water quality, heavy feeding, and UV sterilization/ozonation). Safe acclimating procedures is another overlooked area.
The Blueface angel was quarantined at a local store and appeared very healthy over a two week period that I observed it. We don't have room to QT such a large fish so it was decided that it was the lesser of the two evils to add it directly to the tank while there were few fish and corals and it could be easily caught. Thus far, the tank has only had relatively ich-resistant fish such as anthias, wrasse, gobies and blennies. This was by design, with more sensative fish like angels, tangs and butterflies coming later. We have two tangs in QT now and they will be medicated before addition. Quinine is soaked into the fishes tissue and remains there for 10 days, while it only lasts in water for two, due to photo-degradation. By treating the tangs with quinine just before moving them to the display tank, they get a 10 day protective coating that will ward off protozoans like cryptocaryon.
Blennies and gobies are particularly well adapted to hyposlainity since many of them live in tidal areas where salinity ranges. Hyposlainity, metronidazole and quinine are adequate for treating cryptocaryon but not effective against amyloodinium which is far more fatal and rapid. Cupramine and coppersafe are ionized or chelated to be safer, but gobies and blennies are "scaleless" fish which are very sensitive to copper. If the level is too high, they may jump out or die. Often these fish are more sensitive to copper than the well protected amyloodinium cysts under the safe mucous coating of the fish or on gill plates. Copper medications deplete the fishes immune system. In the end I feel that it does more good than bad, but not in the case of ich resistant fish like gobies and blennies. The negatives have outweighed the positives of adding copper thus far, but we are at the point of using it now, particularly with winter temperature fluctuations during shipping, and the time for tangs, angels and butterflies approaching.
One problem we have with our QT is the aragonite sand and live rock, as they readily absorb copper medications and can release them later. We will be adding a hospital tank some time soon, once we make some space. We may be better off stripping (removing substrates) some of the tanks in the MARS system and running them on air-driven sponge filters with a lower water level. This way we can dose elevated levels of antibiotics and other meds for short periods, then dilute them down to standard therapeutic levels. Sterilizing tanks with chlorine and moving fish helps break the parasite cycle, but netting fish is counterproductive as it damages fish tissue.