In order for us to provide the best possible help . . .
In order for us to provide the best possible help, please provide the following information. It will really help us and it will be information we need.
3. What is SG of this aquarium? How measured?
4. When was the last fish added to this aquarium?
5. Was it quarantined? If so, how? And how long? Was it prophylactically treated? How?
7. If you are using hyposalinity, how did you calibrate your refractometer?
8. Please describe in detail, the appearance of the fish? If there is one or more pimples, are they lumpy? What color?
9. Please describe the behavior of the fish as best you can. Is it acting reclusive? Is it always up towards the top of the aquarium? Is it avoiding light? How active is the fish?
10. Is the fish eating? What?
I eliminated the generalized diagnostic questions and limited it to those applicable to hypo.
As mentioned in the stickie:
Hyposalinity: how-to; when-to; how-long-to
Copper, while a good ich cure, has some problems: angels, puffers, and lions I have seen reported as having difficulty. Plus it depresses appetite.
Hyposalinity is the alternative, and it has one drawback: difficulty in application. This is how you do it: and two things would really make it much easier: an ATO for your hospital tank and a refractometer.
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First, this is a treatment for parasites---including ich---NOT for a bacterial infection.
Second, you should NOT combine this treatment with copper.
Third, do this in a completely bare tank, no substrate, no rock, and with filter material changed daily, and a POTENT little pump: an airstone or powerhead is advised. Do NOT rely on the weak little trickle pumps that are supposed to let water linger over biomedia. Get something that produces a lot of bubbles and that moves water strongly. Why? This is a little tank. It gets tricky because your fish can be in hypo and be fine---but the minute you bring the water back to standard salinity, they'll go oxygen-short, because a rise in salinity diminishes available oxygen. If you have a strong pump, they'll be fine.
Why a bare tank? Because when under assault, the ich will encyst and drop off the fish to attach to sand, rock, or filter media. Get rid of media daily. Because the visible ich has left your fish is no guarantee it's gone. [hint: I go to the hobby store and get a big bag of polyester pillow stuffing; wrap a tuft of that cheap stuff around a teaspoon of carbon---yes! you can use carbon while using hypo, another virtue---and use that for your filter. You can rig a very potent little filter with an old CD holder: put the pump in the bottom, put pillowstuffing atop, and let 'er rip. It's a pot filter, which I use in my koi pond, and it is pretty efficient. Couple that with an air filter with a bubble wand, and you've got plenty of filtration and plenty of oxygen.
LET ME ADD, however, that IF you are dealing with angels, and some other very sand- or rock-dependent fishes, you may find it adviseable to use the OTHER attribute of hypo, which is that it will not totally kill a sandbed or live rock, nor depress a fish's appetite. If you have a cycled qt, with all of the above, despite the propensity of ich to dive for a sandbed, you may find it easier on the fish to use hypo, expect some sandbed and rock dieoff [so be very careful about feeding], and expect to lose all your little inverts, relying on the hypo procedure to kill off the ich and render the cycled qt safe for use for other fishes. Having a hob skimmer as well as a topoff on this system would be adviseable. I would advise waiting 8-12 weeks at regular salinity with the qt tank fishless, but recovering its microlife [a little wad of fresh cheato is good for this] and letting ich absolutely, definitively die out, before another quarantine. You can survive 8 weeks without buying another fish, eh?
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Now---the procedure.
Catch your fish, put him [them] in the hospital tank at regular salinity, and, over 48 hours, slowly lower the salinity in the hospital tank to 1.009. Draw a 'fill line' on your glass, and keep it exactly that. No rise and fall---that favors the parasite surviving. Keep the pressure unremittingly on the parasite, no letup. You should see happier fish soon, return of appetite, etc.
Observe your fish daily, and when you have seen the last ich gone from the fish [remember to change that filter medium daily!] and it's breathing well [no ich in the gills] then you start a 4-week countdown. That's one full month of continued hypo counting FROM THE LAST OBSERVED CYST.
Keep changing that filter medium daily.
At the end of the 4 weeks, over 48 hours, or by topoff with salt water, bring the salinity up to standard-normal. AND WATCH THE OXYGENATION. The fish may have depleted the oxygen during the hypo period, when the water holds more oxygen. As you add salt, the ability of the water to carry oxygen drops proportionately, so energetic oxygenation of the water is very, very important now. Watch the fish for another 7 days to be sure you got it all---and if he remains ich-free, he can go back in.
Most reports of failure of hypo I suspect result in less than exacting application of this treatment. It is precise, it requires a lot of filter changing, and it requires you to keep that water exactly at that fill line: you're on a knife's edge between what the fish can tolerate nicely, and what will kill inverts like ich. You need to stay right on that line.
But because it lets you use carbon, and doesn't depress appetite it may be the best and gentlest course for a fish that is already weak or not eating well, and it may be best for some species.
Hope this helps.
