O.K. I must correct the record here...
This is a quote from <a href="http://www.about.com:" target="_blank">www.about.com:</a>
Greenex by Aquatronics is a combination of malachite green and quinine hydrochloride, and has given us excellent results in a couple of days. We generally treat for a five to six day period, following the product dosage instructions. Greenex is invert (meaning crustacean) safe and does not weaken or kill your biological filter base. When we have used Greenex in our invert tank, with some live rock in it, it does not seem to harm the live rock. However, we have had reports from some people that malachite green may harm certain corals, so it may not be completely reef safe. If you decide to treat your main tank, the down side of Greenex is that it will turn any silicone, air tubes or anything that it touches blue, except the fish. Once again, using a QT is a good idea. It is suggested to remove any delicate inverts or corals from the tank and place them in a separate aquarium.
Ed I have followed alternative treatments for ich for many years and the use of quinine/quinicrine products is one of them that has gained some acceptance in the last 10 years, i.e. the intro/advent of the "Greenex" product. Aquatronics used to make a solely quinine based product prior to introducing Greenex.
My experience with Greenex has been good. I have used it with success in FO Fish Only setups many times and had no notable decline in my bio-filter. A few times I have used it with crabs in my system and they survived. CURRENTLY I NO LONGER USE ANY MEDS INCLUDING COPPER, GREENEX, FORMALIN, OR ANTIBIOTICS, unless it is absolutely necessary after a 1 month quarantine period using HYPOSALINITY only!
For all you out there that have corals/inverts who do not wish to put forth the time, expense, and effort perhaps greenex is a quick alternative, but is by no means the preferred treatment.
Star Fish1 I am not sure if you have lost any fish, if you have I doubt it was due to the Greenex... the parasite infestation was probably too far gone and along with bacterial infection the fish could not recover. Also note that hyposalinity needs to be done correctly to be effective. Note that it has no effect on parasites that are already on the fish, only on the part of the life cycle where they have dropped off to the bottom to reproduce into the free swimming stage. Hypo at SG:1.009 or a Salinity less than 16 ppt will not allow the free swimming stage to occur, thus the parasites that are/were already on your fish will still do their damage. I suggest you search this sight for "hyposalinity" and "quarantine" as you will find lots of very informative reading on these subjects. Futhermore, hypo is for fish only, (hence the recommended separate quarantine tank/system) inverts and live sand beds will not survive hypo conditions. Lastly, your Q system must have a active/cycled bio-filter and you must buffer the water to keep the pH up as lower salinity water does not maintain pH as well. Good luck, Joe.