[bettababy]

Ich ("ichthyophthirius") is a parasite, not a viral infection. It is caused by the cilliate "Ichthyophthirius multifiliis", an organism, pear-shaped to spherical in shape and .2 - 1 mm in size. (the macronucleus is horse shoe-shaped and the micronucleus is spherical). Ich spends most of its life on a host fish, feeding off the skin, digging sealed off hollows into the flesh. The parasite has a 3 stage life cycle: 1, growth, spent on the skin, 2, cyst, when it drops to the bottom of the tank protected by a gelatin covering and then dividing, and 3, the infectious stage, when pear-shaped zoospores seek a new host. The cyst can divide into as many as 1000 zoospores, which have 70 hrs to find a new host. Ich is highly contagious, and survivors can acquire an immunity, but many remain dangerous, since they may be carriers without showing signs of the disease. This is why medication is the #1 solution to resolving the issue.
Because of the temperature tolerance limit for the parasite, using aquarium/marine salt treatment of 1 tbsp/5 gallons and raising the temp to 84 degrees should safely rid your tank from the parasite. The salt will affect the parasite and will act as a muscle relaxant for the fish. The use of salt can also help to avoid/prevent the chances of secondary infection in the fish.
One thing to note: Not all fish can do well with salt in the water. If in doubt, please ask for help before putting it into the water. When used as a medicinal treatment, add the salt directly to the tank, slowly, and then stir slightly with your hand to circulate it. If you premix it into a small amount of water, the chemistry of the salt changes and you will lose the benefits of using it at all.
An experiment to try: Take a small cup, add a large amount of salt to the dry cup, then slowly add just a little bit of water, and hold the cup in your hand, with the bottom of the cup resting in your hand. If you hold it for a few minutes, you will notice the cup becomes warm, sometimes to the point of not being able to hold onto it. Now, take another cup, same kind of cup, or reuse the same cup after rinsing it thoroughly. Add water to the cup, and then slowly add salt. There should be no temperature change. The chemical reaction between the salt and water differs according to concentration and in which is put into the container first.
When medicating using salt, if the salt is added slowly, it will not burn the fish, considering it is a fish that does NOT have a low tolerance for any salt.

 

[Lupin]

Picture has been added.

Picture taken from The Complete Aquarium Guide by Konemann.

Pls treat the whole aquarium for two weeks.
Frequently asked questions:
Frequently asked questions:
1. Why is it recommended to treat the whole tank instead of isolating the afflicted fish?

This is a question which is easy to answer yet some people fail to realize that ich does not stick only to the fish (carrier). Bear in mind that if the fish is introduced in the main tank with ich, the parasites will target any fish with weakened immune system. Weakened fish are more likely to succumb if stressed severely.

2. How does ich appear?

Ich will appear if the fish is stressed. Note that it acts more like a 'contaminant' and is not part of the tank's ecosystem. Any new fish should be quarantined for 2-4 weeks. Failing that will increase the risk of introducing diseases which wil affect other occupants. New fish are always possible carriers of diseases.

3. How do we kill ich?

Increase the temperature to at least 84 degrees and treat the tank accordingly with proper medications or salt. Follow the instructions carefully. Any overdosage may prove fatal to the fish especially scaleless ones.

4. Why is it recommended to treat the fish for at least two weeks?

The combination of the temperature and medication/salt can kill most ich parasites but do note that ich is not vulnerable in cyst form and under the fish's epidermis. They are at their highest vulnerability when in free-swimming stage where they are exposed to the conditions they cannot tolerate. Two weeks is long enough to guarantee the elimination of most ich parasites while they go on with lifecycle stage triggered by the high temperature. Ich will most likely reappear when the fish becomes stressed again unless the treatment process is completed.

 

[bettababy]

To add to Blue's post...

If using salt and higher temps to treat ich, then please make sure your fish can handle the salt and higher temps. NOT ALL FISH CAN TOLERATE SALT OR HIGHER TEMPS.

If using meds to treat ich, please be sure that it is a safe medication for all of your fish... NOT ALL MEDICATIONS ARE SAFE FOR ALL FISH.

VERY IMPORTANT: Know your water params for ammonia, nitrite, nitrate, and pH BEFORE medicating. ANY ammonia or nitrite, or nitrate levels over 40 - 60 can be very dangerous mixed with medications, and can cause an adverse effect on the fish.

If you are in question about which medications are safe, about whether your fish can handle the salt and/or higher temps, etc... please ASK BEFORE you take any steps in treating this problem. There are a lot of ich medications on the market, not all of them are for you and your fish. With basic tanks specs, (size of tank, number and species of fish in it, water params for those listed above, how long the tank has been set up, feeding schedule, and anything else you can tell us about your tank and your fish) I can help to determine the best meds for you to use. Without the listed information, nobody will be able to help, so please be sure to include that info in your FIRST post.
Thanks!

 

[Lupin]

"Dormant Stage"
http://www.skepticalaquarist.com/docs/health/ich.shtml

Only the trophont can persist "dormant" in the aquarium, though it's never free-living but always attached inconspicuously to a host, perhaps on a gill surface.

There is no "dormant" independent, long-term encysted life stage separate from a host fish for Ichthyophthirius multifiliis.

Ich myth. ...now you have no excuse for imagining that Ich has a dry spore stage that gets blown through the air and settles on the water, or that it can be transported in an aerosol mist or on a net that has air-dried overnight: "its spores are everywhere. in your tank. on your hands" writes a respected and usually knowledgable aquarist ...but you have no excuse for fearing that Ich is always lurking in your tank water, or even in your drinking water, or that it lies low in the gravel, dormant but just waiting for a cold spell to burst into action, etc etc... all Beemer: Bogus Misinformation Endlessly Repeated. Most Beemer isn't pure invention, but is based on some misinterpretation or mis-hearing of fact. If you keep a steady grip on the facts of Ichthyophthirius life stages, you may even be able to disentangle the particular misunderstanding that's at the root of each particular Ich myth.

It's possible that the myth of Ich "lying low" in the aquarium in an imagined "dormant" stage, may have come from confusing Ichthyophthirius multifiliis with a similar marine ciliate parasite called Cryptocaryon irritans. People like to call Cryptocaryon "Ich's marine counterpart." In marine aquaria, I'm told, Cryptocaryon (which means "hidden spore") can remain infective for up to thirty days, especially at low temperatures! If this is true, it's an insidious parasite, and much more difficult to eliminate than our familiar freshwater ciliate. But perhaps a habit of confusing the two--— by calling them each other's "counterparts"--— has helped create the myth of a counterpart "dormant" life stage for Ichthyophthirius multifiliis.