Originally Posted by The Bunk
I made my frist major mistake in reef tanks a few weeks ago, and became the poster boy for QT tanks. I bought a fish that had ich (unbeknownst to me) and put him directly in my tank. Within two weeks all but two fish in my tank were dead. I'm fighting an uphill battle to save the last two I'm afraid. I won't be buying another fish until I get my QT tank setup.
I've never run a QT tank, though I probably should.
The problem is that marine ich is something of an ornery little shit. Wild-caught fish all have it and virtually any distributor is going to run a mass filtration system that will pass it around as well. Freshwater ich is a different creature entirely; it's much more rare. Marine, on the other hand, is virtually everywhere and extremely difficult to ever completely eradicate, especially once it is introduced to your system.
There are 2 theories here w/ marine ich - the first is that leaving your tank fallow for about 3 months will essentially starve the ich out. What you see when you see ich is actually the little cysts that form as it 'hatches'. What emerges falls into your substrate, rocks, etc... and then attaches to the fish. Rinse/repeat, so long as there are fish in the tank. By going fallow (without fish; inverts like corals and a cleanup crew would still be fine), you leave them nothing to attach to. You have to stay fallow for a long time to ensure that you don't have any stragglers that have stayed dormant for the whole period.
I tried going fallow; ran the tank empty for 6 weeks and the first two fish in introduced were baby clowns that were bred by a local breeder. Within a week, they showed spots. I gave up. Oh, and all of the fish I removed from the tank to go fallow with it died in quarantine due to the stress of the small tank.
A QT tank has to be barren to avoid the ich having anywhere to breed. Further, you want it to induce a little stress in order to start that ich lifecycle in your QT in order to fully eradicate them. That said; I still don't trust it unless you're willing to do a 6-week QT, and even then, the malachite green and copper and formaline and all that stuff can start to have a negative impact on fish as well. Hypo-salinity (really low salt levels) is the safest option, but it's actually quite difficult to do well and can also be hard on the fish.
Oh...and I'm sure (I hope) that you know that virtually any treatment for ich cannot go into your reef. All of that stuff will kill your inverts, generally including your corals. It will get into your live-rock and never really cycle out. Worse still, it will get into your seals and run the risk of making that tank 'radioactive' in the future.
Theory 2: Nutrition and stability. Most folks now believe that if you go about 6 months without introducing 'new' ich to the system, it will essentially inbreed itself out of useful existence in your tank. I've only gone a prolonged period of time without adding anything once, and there seemed to be some merit to that as nothing showed spots ever, regardless of stress. Others will suggest that fish can develop something of an underlying immunity to it if they've had it; I don't buy that one. I simply believe they get more comfortable in their surroundings and they fight it off without it becoming visible.
What I do to address ich is simply feed a lot, feed quality food and dip it in garlic and Selcon. Additionally, try to increase your water movement to ease the strain on their gills as Ich will first attack their respiratory system (it's why you see really sick fish hang out up high and around the returns). By moving the water more, you introduce more oxygen to it and its easier for them to breathe even if their gills aren't at 100%. I've heard of people doing really well by adding a live-well aerator to get more oxygen in the water.
The Selcon is actually far more important than the garlic. As has been noted, garlic just increases appetite. The useful enzyme in garlic for health purposes has long since broken down by the time it gets to your house, let alone your tank. The Selcon, however, adds a lot of acids and fats that are very healthy for your fish (if you have tangs, get it to prevent lateral line erosion).
Water changes are also a big deal. People forget that the salt is more than just salt; it has a bunch of minerals and stuff in it that are pretty helpful for having healthy fish.
By keeping the fish healthy, fed and happy, you can fight them through that 'cyst' period. The cysts will hatch and fall into the substrate and your fish will look better briefly. They will be healthy and less stressed due to the feeding and water changes and they'll be able fight off secondary infections and
have an immune system that can fight off the ich when it re-emerges and tries to attach again.
It's simply a matter of fighting through it, IMO. Keep 'em healthy and fed and you'll find that most marine fish are adapted to fight off ich. Some are pretty lousy about it (my hippo seems to always have it but that thing eats like a pig so it pulls through easily), some never get it (haven't seen a spot on those baby clowns in 18 months now; I think adding the anemone has them pretty relaxed so they never show it).
But there's really no reason for ich to be a tank-killer and more often than not, the 'cure' is worse than the disease. Try to set up the QT if you want, but I've never had the patience for them. More than anything, I think they're great for getting fish to start eating before introduction into a display, but they're of limited utility when it comes to actually keeping ich out. (Marine velvet and other more nasty boogeymen, on the other hand, it will keep out).