White Spot or Ick Is A Common But Easily Treatable Fish Disease

white point

White spot disease is caused by a parasite called a parasite. Ichthyophthirius multifilis. This disease is also called Ick or sometimes Ich or Ichy.


There are white spots on the skin of the fish. The spots are the size of a pinhead and may look like the fish is sprinkled with grains of salt or sugar. The parasite also attacks the gills of fish. This is harder to see. The gills may appear redder than normal, but this is difficult to see and many things can cause extremely red gills. The gill infection makes it difficult for fish to absorb Oxygen from the water, and infected fish may show signs of Oxygen deficiency, such as “breathing” at the surface or apparently breathing too quickly. Many things can cause this Oxygen shortage.

Sometimes fish try to rub their skin against objects by swimming. This is called “flashing” and can be caused by any skin irritation.

Sometimes fish do not show obvious symptoms, they just die. If a fish dies, you should take a very close look at all the fish in the tank.


This is a very common fish disease. The parasite is found at low levels in most aquariums and usually does not cause any problems. Most fish have been exposed to this parasite and have developed some immunity. Fish raised in the complete absence of the parasite will not have this acquired immunity and will be very vulnerable to infection.

The statement that this parasite is found in most aquariums is often misunderstood. Ichthyophthirius Multiphilis cannot stay asleep for long. It survives by living on fish. There may be no fish in an aquarium for a month. It will be free from white spot interference. A fish without any visible disease was then purchased and quarantined. This fish can be introduced into an empty tank and white spots may appear. An erroneous conclusion can be made that either there is a dormant white spot in the empty tank or the quarantine was not done correctly.

What would have actually happened would have been that the fish had had a white spot infection without any symptoms. A successful parasite does not make its host sick. If the parasite wipes out all the fish in the aquarium, pond or lake it is in, the parasite itself dies. In the wild, the white spot parasite is apparently successful and often does not kill its host. In an aquarium’s unnatural ecosystem, it can easily get out of balance and kill all the fish. It is not only fatal to fish; It is also deadly for the parasite.

The ideal parasite is one that actually provides some advantage to its host. As far as I know, having a white spot parasite is not an advantage for fish, but other parasite/host relationships may have evolved into symbiotic relationships where both organisms gain an advantage.


If something is stressing the fish, the immune system often becomes less effective. The same effect can be observed in humans. When you’re under stress, you’re much more likely to get both minor and major illnesses.

There are many things that stress fish. A very common one is simply being caught, put in a plastic bag, and moved to a new home. A common time for a White Spot outbreak is right after a new fish has been added. Some people mistakenly assume that the new fish introduces the parasite. They can then go back to the shop where they brought it and see that the tank the fish came from is perfectly fine.

Other types of stress include changes in temperature, pH, dH or any other water parameter.


Ichthyophthirius Multiphilisobligate parasite. This means that it can only live in the presence of fish. The real-looking white dots are the feeding stage called the trophont. The trophont grows and then falls off the fish, falls to the bottom of the tank and forms a cyst called a tomont. Up to 1000 tomonts can form inside the tomont. Tomont opens and the tomits enter the water.

time needed for Ichthyophthirius Multiphilis Completing its life cycle depends on the temperature of the water. At 6 degrees C (43 degrees F) it completes its life cycle in about 55 days, at 29 degrees C (84 degrees F) it completes its life cycle in only about 4 days.

Tomites must find a fish quickly, or they will die. At normal tropical fish tank temperatures, they have only 2 days to find a fish to infect.


Although successful treatments with salt baths have been claimed, the trophy on fish probably cannot be successfully treated. Although tomonts at the bottom of the tank can also be removed with a gravel wash, they are difficult to kill. Keeping the tank clean will help.

The only stage that is easily susceptible to treatment is the free-floating tomite. This can be killed by many things, including heat, ultraviolet light, salt, and many other chemicals.

There are many possible forms of treatment. All the different ways of killing the parasite suffer from the problem that there are many strains of this parasite and their susceptibility to treatments is different. Here are a few ways to treat this disease:


There are many commercial treatments for whiteheads. Usually Methylene Blue, Malachite Green, Formaldehyde, Ariflavin etc. they use some combination of chemicals. My preferred drug in our own tanks is Wardley Ickaway, but different people will have their own preferences.

Note that these drugs are absorbed by activated carbon and will need to be turned off if you have carbon filtration. Most drugs are also destroyed by ultraviolet light, so ultraviolet sterilization will also need to be turned off.

Scaleless fish such as tetras and other Characins, loaches and catfish, as well as baby fish, are more sensitive to many of these drugs and should be used at half the normal rate. You can use the half rate as twice the normal frequency.


The life cycle of this parasite is greatly accelerated by heat. Increasing the temperature will make the chemical treatments work faster, but will also mean the infection will spread faster.

However, if the temperature is raised enough, the parasite cannot multiply and the infection can only be treated with heat. However, some fish species cannot survive in the temperature required to destroy the white spot. To break the life cycle of this parasite, you need to raise the temperature to about 30 degrees C (86 degrees F). To really kill the parasite you need to raise the temperature to about 32 degrees C (89.6 degrees F). This temperature must be maintained for at least four days to have a good chance of killing the parasite. Not all fish will survive this treatment, and many will be badly stressed by it. As Oxygen does not dissolve as much in warm water, more aeration will be required and as the water gets warmer, the fish’s metabolism increases, so more Oxygen is required.

If you are treating Maze fish such as Siamese Fighting Fish, Gouramis or Paradise Fish, this treatment method is sometimes the preferred method. These fish can survive the required temperatures and breathe air as well as water.


Some people have reported success in treating this disease with the careful use of chlorinated tap water. Personally, I wouldn’t try it and would advise other people not to try it. The actual Chlorine level in the water from the faucet varies not only by region, but also by the day of the week and the season of the year.

Aside from the difficulty of getting the chlorine dose right, there is also the issue of having Chlorinated water in some places like the Adelaide Hills where I live. This is fatal to fish and I wouldn’t risk using the water without dechlorination.


Salt kills the white spot parasite, but different strains have different tolerances. Most types of whiteheads will be killed with 3 grams of salt per liter, but you will need to use 5 grams per liter to be sure.

This means that many common goldfish cannot survive at the salt level needed to kill white spot. Generally, this treatment method is not suitable for fish that come from places where there is not much salt in the water, such as the Amazon, Congo and Orinoco rivers.

It can be used on livebearers such as Guppies, Mollies, Platies and Swordtails. It can also be used with some Australian fish such as Murray Cod, Silver Perch and Callop, but cannot be used safely on Rainbowfish.

Most aquarium plants die from this salt level.

ultraviolet radiation

Ultraviolet light kills the free-floating tomite stage of the parasite, but can only work on tomites that have been absorbed from the ultraviolet sterilizer. You are more likely to get good results if the ultraviolet unit is more powerful than what is usually recommended for your aquarium.

An ultraviolet filter will help prevent white spot, but cannot be relied upon to cure it.

Disease Free Fish

It is possible to breed fish in the complete absence of the white spot parasite. This happens with most live carriers bred in Malaysia. These fish are bred in water that is a mixture of freshwater and seawater, sometimes half the salt concentration of pure seawater. These fish will never be exposed to white spot and some other diseases and will be very sensitive to them. These fish can be quickly destroyed. If purchased, they need to be observed and treated quickly if necessary. Aquarium stores normally warn their customers that the fish are disease free.

Secondary Infections

White spot infection damages the skin of the fish and it is common for bacterial or fungal infections to occur along with the white spot.

Responsive Fish

Some fish species are more susceptible to white spot disease than others. The Clown Loach has a particularly bad reputation for contracting this disease.

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