Here's a good explanation I got off of Wiki How To. I copied down to "Easy Ich Treatment" (raising temp to 86F). If you go to that site it also talks about using salt or medicines for stubborn cases.
Most people here recommend the 86F Temp method, which is usually the simplest and safest way.
How to Treat Tropical Fish with White Spot Disease (Ich)
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PARTS
1Understanding How Ich Works
2Easy Ich Treatments
3Intermediate Ich Treatments
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Article Summary
Co-authored by Pippa Elliott, MRCVS
Last Updated: November 12, 2022 References Approved
White spot disease, also known as Ich, is a parasite that most tropical fish enthusiasts will, at one time or another, have to deal with. White spot disease is responsible for more fish deaths than any other disease. This disease is mostly found in aquarium fish due to close contact with other fish and stress involved in living in an aquarium as opposed to the open water. Ich can be found in both freshwater and saltwater tropical fish with different ways to treat each ecosystem and its inhabitants.
Part1
Understanding How Ich Works

1
Distinguish white spot disease between freshwater fish and saltwater fish.The disease works in the same way for both freshwater and saltwater fish but have different life cycle durations and different cures. In both types of water, the protozoan parasite attaches itself to fish in order to carry out its life cycle. In the wild, ich is less of a problem as few parasites are ever able to find a host. When they do, the parasites eventually fall off of the fish and the fish is able to swim away and heals its wounds. However, in an enclosed tank, ich parasites can easily attach itself to fish, multiplying and infesting, which eventually leads to the decimation of an entire tankful of fish.
- In freshwater, ich is known as ichthyophthiriasis. [1]
- In saltwater, ich is known as cryptocaryon irritans and is often confused with other parasites that produce white spots. Saltwater ich can take longer than freshwater ich to replicate but only have 12 to 18 hours to find a host before they die as opposed to freshwater ich which can last up to 48 hours without a host.

2
Understand that stress is a factor that affects the likelihood of ich.Since ich is fairly common, most fish have developed a good immunity against it. However, stress can suppress the immune system of a fish and that's when ich is most prevalent. Stress can be caused by:
- Incorrect water temperatures and bad water quality.
- Other tank inhabitants.
- New tank inhabitants.
- An improper diet.
- Shipping and handling of fish during transport
- Your own home environment, especially if your home is prone to loud noises, banging or shaking doors, or have a lot of traffic around the tank.

3
Learn to identify symptoms of ich. Symptoms of ich can be seen on your fish as well as in the way your fish behaves. The most obvious sign of ich is the appearance of little white dots that resemble grains of salt which gave the disease its name.[2]The common signs and symptoms of ich are:
- White spots on the body and gills of fish. The spots may even join together to form white patches. Sometimes, the ich is only found on the fish's gills.
- Excessive flashing. Your fish may excessively rub against plants or rocks in the tank in attempt to get rid of the parasites or because the disease is causing the fish irritation.
- Clamped fins. This means your fish constantly folds its fins against its body instead of letting them fan out and rest freely by its sides.[3]
- Laboured breathing. If your fish is gasping at the surface of the water or hovering near the tank's filter, it's probably suffering from a lack of oxygen. The ich on its gills makes it difficult for your fish to absorb oxygen from the water.
- Loss of appetite. If you fish is not eating or spitting back out its food, this may be a sign of stress and disease.
- Reclusive behaviour. Animals often hide when they're feeling ill and any change in normal behaviour is often a sign of stress or disease. Your fish might hide out in the decor or not be as active as usual.

4
Treat your fish for ich when the parasite is most vulnerable.Ich can only be killed when it is not attached to the fish which is when the fully matured parasite drops off of the fish's skin in order to replicate itself into more ich-infecting units. Anytime the parasite is attached to the fish, it is protected from chemicals and treatment is not effective. There are several stages to the ich life cycle:
- Trophont stage: This is when the ich parasite is visible on your fish. It burrows under your fish's mucus coating forming a cyst which protects it from chemicals so that any treatment becomes ineffective. In a typical tank with a temperature of 75 to 80ºF (24 to 27ºC), the trophont stage or feeding stage will last a few days before the fully developed cyst drops off the fish.
- Tomont or tomite stage: At this stage, treatment of ich is possible. The parasite or tomont will float for several hours in the water until it attaches itself on a plant or some other surface. Once attached, it begins to divide or replicate rapidly inside the cyst. In a few days, it will burst open and new organisms will start swimming out in search of a new host. Freshwater tomont can replicate as fast as 8 hours while saltwater tomont may take up to 3 to 28 days to replicate.
- Thermonts or swarmer stage: Freshwater swarmers must find a host or fish within a 48 hours or it will die while saltwater swarmers only have 12 to 18 hours. For this reason, one way to ensure a tank is clear of ich is to leave it uninhabited for a week or two.

5
Observe the temperature of your tank.Higher temperatures speed up the life cycle the parasite. A tank with a higher temperature will take a couple of days for the cycle to complete while one with a lower temperature may take weeks to complete.
- Never increase the temperature of your tank drastically. This can stress your fish and some fish do not tolerate higher temperatures.
- Most tropical fish are can withstand temperatures as high as 86ºF (30ºC). Always consult your tropical fish expert or learn about your fish to find out what temperatures they can tolerate.
Part2
Easy Ich Treatments

1
Raise the temperature of the water to 86ºF (30ºC).Slowly increase the temperature by 2ºF (1ºC) per hour until it reaches the correct temperature. And maintain this temperature for at least 10 days. High temperatures speed up the life cycle of ich and can also prevent tomont from replicating.
- Make sure that the other fish in the tank can handle the higher temperatures beforehand.
- If your fish can handle temperatures higher than 86ºF (30ºC), raise the temperature to 89ºF (32ºC) for 3 to 4 days and then decrease it back to 86ºF (30ºC) for another 10 days.
- Be sure your tank has enough oxygen or aeration as water holds less oxygen at higher temperatures.
- At the same time, you can treat the water with salt or medicine everyday.
- Always be sure your fish can handle a rise in temperature. Observe how your fish react to a slowly heating tank or read up on how high of a temperature your fish can tolerate.