The Secret to Diagnosing and Treating Freshwater Ich

One of the most common diseases that freshwater aquarium fish will be infected by is Ichthyophthirius multifiliis, also known as Ich or White Spot Disease. This article will give you some valuable tips for treating and preventing Ich. 

No matter how careful you are about quarantining new fish and maintaining high water quality, your tank may still experience an outbreak of an aquarium fish disease.  One of the most common freshwater fish diseases is Ichthyophthirius multifiliis, more commonly known as Ich. This disease is not only common among freshwater fishes but it is also highly persistent and contagious. If you do not keep a close eye on your fish and take action to treat Ich as soon as it appears, you could very well have a tank-wide infection on your hands. In order to protect your fish against this disease it is wise to learn the basics about its symptoms and treatment.

What is Ich?


One of the most common freshwater aquarium fish diseases, Ich is caused by a protozoan parasite called Ichthyophthirius multifiliis. This protozoan parasite is an ectoparasite, meaning that it lives on the skin of its host. Ichthyophthirius multifiliis is also an obligate parasite which means that it cannot survive outside the host body. When it first attaches to the host body the Ich parasite lives within a nodule inside the skin or gills of the host fish, feeding on it. During this period of growing and feeding, the parasite is called a trophont.


After a time, the parasite begins to divide through the process of binary fission and leaves the host, dispersing itself among the plants, gravel and ornamental objects in the aquarium. Once it reaches this stage, the trophont becomes a tomont and it produces sticky, capsule-like cyst that allows it to adhere to almost any surface it comes into contact with. While inside the cyst, the tomont may produce as many as 3000 tomites which then break out of the cyst as theronts and actively seek out a new host body to infect.

Symptoms of Ich


ichIch is also commonly referred to as Whitespot Disease because the main symptom is the appearance of tiny white spots on the bodies of infected fish. These spots typically pop up on the fins, gills and body of infected fish and may be as large as 1mm in diameter. Other symptoms of this disease may include loss of appetite, rapid breathing, flashing, resting on the bottom of the tank and rubbing against tank objects. When a fish first becomes infected with the parasite it is not likely to show any symptoms at all but the disease progresses fairly quickly and it does not take long for the body of the fish to become covered in white spots. Click the image of the cichlid for a better view.


Recommended Treatment Options


If you catch the symptoms of Ich before it has spread to any other fish in the tank, it would be wise to quarantine the infected fish. You should still dose the entire tank to kill the parasite, however, thus preventing further outbreak. Removing the infected fish as an added precaution may help to preclude the spread of the disease to other fish. The first thing you should do in treating this disease is to slowly begin raising the temperature in both the main tank and the quarantine tank. The life cycle of the Ich parasite typically lasts around two weeks but higher temperatures will shorten the life cycle of the parasite. The more quickly the parasite progresses through its life cycle, the sooner it will become susceptible to medication. Remember to increase the aeration and/or water surface agitation to increase oxygen levels since an increase in water temperature will cause a decrease in available oxygen levels.


Two of the most common commercial medications recommended for Ich are Formalin and Malachite Green. If you choose to utilize a chemical treatment, read the dosing instructions on the bottle carefully in order to determine how much to use. If you have scale-less fish like catfish in your tank, cut the recommended dosage in half. When treating your tank with any kind of chemical medication it is necessary to remove any activated carbon from your filter because it will remove the medication from the water. Treat both the main tank and the quarantine tank for a period no shorter than 10 days to ensure that the parasite has been eradicated. During this period, observe the fish in your tank for signs of secondary infections which are fairly common in fish that have already been weakened from a parasite attack.


Another common treatment for external parasite infections like Ich is salt. Regular uniodonized table salt can be used for this purpose, as can aquarium salt and Epsom salt. In order to treat Ich using salt, prepare a 0.3% solution to dip the most infected fish. To achieve this concentration, mix approximately 3 teaspoons of salt per gallon of water in a separate container. Dip the infected fish in the solution for no more than 3 minutes then return it to the hospital tank. Dosing the entire tank with 1 teaspoon of salt per gallon can also be effective. If you choose this option, repeat the treatment every 24 hours.

Tips for Preventing Ich

Although it has already been said that quarantining new fish and maintaining high water quality is no guarantee that your fish will never fall ill, these steps are two of the best ways to prevent Ich from ever entering your aquarium. It is not uncommon for pet store tanks to become infected with Ich – it only takes a single fish to infect an entire tank and the chances are good that, after the shipping process, the fish in overstocked pet store tanks are already stressed. Bringing home a fish that has been exposed to or infected with Ich is the most common way the parasite is likely to enter your aquarium. If you quarantine all new fish for at least two weeks you can greatly reduce the chances that you will accidently introduce the Ich parasite into your tank. While your new fish are in quarantine you can observe them for signs of the illness and treat them if necessary.

Maintaining high water quality in your tank is essential for keeping your fish healthy. Happy, healthy fish are much more equipped to evade a parasite infection like Ich and, in the event that they do contract the disease, they may also be more likely to recover successfully. Keep up with your routine water changes on a weekly basis and always change your filter media every month to ensure that the water in your tank stays fresh and the toxin levels are low. If your tank is clean, your fish are less likely to become stressed and thus less susceptible to contracting diseases like Ich.
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