Ich or White Spot Disease: Causes, Symptoms and Treatment

PetGuide
PetGuide logo

Just like any organism, aquarium fish are prone to certain diseases. Ich, also known as white spot disease, is one of the most common diseases affecting aquarium fish and it is also one of the most contagious. To protect your fish from this disease you should learn everything you can about it including its causes, symptoms and treatment options.

Presentation and Causes

Ich is the short name for this condition – its official name is Ichthyophthirius multifiliis after the protozoan parasite responsible for the disease. The protozoan that causes Ich is an ectoparasite; this means that it resides on the outside of the host body. Ich presents in the form of tiny white nodules that look like salt grains on the body, gills, and fins of infected fish. Each spot represents an encysted parasite and a single fish can carry dozens of them at once. The disease is very damaging for fish because the parasite feeds on the host before falling off and reproducing somewhere in the tank.

Symptoms and Progression

The most obvious symptom of Ich is, of course, the white spots on the body, gills, and fins of infected fish. Infected fish may show other symptoms, however, including loss of appetite, rapid breathing, lethargy, flashing against tank objects, and other changes in behavior. The progression of the disease is determined by the life cycle of the parasite. The white spots appear when the parasite is encysted and feeding on the host body. Next, the parasite falls off and adheres to a surface in the tank where it divides up to 10 times, producing infective “theronts” which then attack the fish.

Treatment Options

Ich is a highly contagious disease which is why it is recommended that you treat the entire tank rather than trying to quarantine the infected fish. Even if you only see white spots on one fish, it is likely that all of the fish in your tank have been infected. The parasite responsible for Ich does not have a dormant stage, so it won’t be waiting around in your tank for your fish to become weakened by some other factor. Of course, stress and other factors that reduce the immunity of your fish can accelerate an outbreak of Ich.

One of the most important aspects of treatment for Ich involves speeding up the life cycle of the parasite – this can be accomplished by increasing the tank temperature by a few degrees. This treatment is only recommended for fish that can handle higher water temperatures, it is not good for cold-water fish like goldfish. This heat treatment should be paired with another form of treatment like salt baths and medications. Adding aquarium salt to your tank or treating individual fish with salt baths can help to kill the external parasite. Medications that are likely to be effective against Ich include formalin, malachite green, methylene blue, copper sulfate, and potassium permanganate. Just be sure to follow dosing instructions carefully and remove any activated carbon from your filter before dosing your tank.

If you have a fish tank, you will probably deal with an outbreak of Ich at one time or another – that is how common this disease is. There are, however, things you can do to help prevent Ich. The main thing is to keep the water quality in your tank high and to feed your fish a wholesome diet to keep them in good health. You should also quarantine new fish for at least two weeks before adding them to your tank so they don’t spread any disease, Ich or otherwise.