Whitehead disease: cause and treatment

Do tiny white spots appear on the body of your aquarium fish? They probably have Ichthyo (white spot disease), a protozoan skin disease that can affect all freshwater fish. Don’t delay in treating this contagious disease as it can infect all your fish and once the gills are affected, they will soon succumb.

Why did my fish get sick?

Poor living conditions

Nothing is enough to trigger the white spot disease: temperature variation, malnutrition, injury, stress, … These various aggravating factors all contribute to the fragility of fish, which are very sensitive to their environment.

The arrival of a new fish

The most frequent cause remains the purchase of a new fish (or a new plant) carrying the parasite. The ones you buy in pet shops are often sick, and the plants sometimes harbor cysts. It is therefore advisable to isolate each new arrival in quarantine for several weeks, and to rinse each plant before introducing it into the aquarium.

How do I treat my fish?

The Ichthyo is only vulnerable at a certain stage of its development: when in its free form, out of the cyst that protected it, it seeks a host. If it fails to find one in the following days, it dies.

The transfers

First, place your fish in a quarantine tank and leave the exhibition tank empty. The larvae of the protozoan, without a host, will die after three days.

In the quarantine tank, increase the temperature to that which is bearable for your fish. This will speed up the development of the parasite, so it will detach from the fish more quickly and fall to the bottom of the tank. After 12 hours, transfer the fish to a second quarantine tank. The parasites that have fallen to the bottom will not have had time to multiply and find a host.

Repeat the operation, cleaning and disinfecting the tanks between each transfer. The total disappearance of parasites can take several weeks depending on the water temperature.


You can also turn to anti-white spot medication. There are many brands and you can easily find them in pharmacies or pet shops. Be careful: not all fish can take them, especially those without scales. In this case, it is usually sufficient to divide the dose.

Whatever treatment you choose, prolong it for three days after the symptoms have completely disappeared to be sure that the disease does not reappear.

Providing good living conditions for your fish will always be the best way to prevent white spot disease. Healthy, calm fish are more resistant to this parasite, so they often develop immunity and treatment is no longer necessary. Always remember to quarantine new arrivals, wash your aquarium and all your equipment regularly, monitor the temperature, …