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Treat ich on fish – understanding, treating, and preventing white spot disease

10 10, 2023

White spot disease – what is it?

At the outset, it is worth mentioning that this disease looks similar in both marine and freshwater aquariums. However, it is caused by two other types of ciliata. They differ in the structure of the macronucleus. In the case of freshwater, it is a disease caused by a parasite called Ichthyophthirius multifiliis (Ich). In marine aquariums, we call this parasite as Cryptocaryon irritans.

These dangerous protozoa can infect any fish species in the aquarium.
Good to know: Did you know that Ichthyophthirius multifiliis as a parasite is large enough to be seen with the naked eye? It reaches up to 1.5 mm in length.

Life cycle of ich:

  • Trophont - This stage is easy to observe, it's characterized by small white spots on the body. Usually, at this stage, the parasite is introduced into the aquarium. Grow up in the body of the fish and then release the next generation into the water (as long as they do not close in cysts again are susceptible to medicines).
  • Tomont - Once encapsulated, the parasite develops in cysts. The cysts settle on the substrate (unfortunately, at this stage, the parasite is resistant to medicines).
  • Theront - Next stage begins when they free themselves from the cysts. The parasite starts looking for a fish host (at this stage, ich parasite is again susceptible to medicine).

What does ich look like on fish – signs of ich

Before giving examples of what are the symptoms of parasites in the aquarium, it is important to know that it is possible to make a mistake during diagnosis. If you are dealing with this disease for the first time, you should contact a specialist as soon as possible after noticing the first symptoms. Characteristic white spot disease is often confused with thrush, which has very similar symptoms.

The main symptoms of ich in the aquarium:

  1. The white dots on the body or gills are a sign of an infected fish.
  2. Loss of appetite
  3. There is noticeably heavier gill work. 
  4. Fish are scratching at the aquarium decorations.
  5. Lethargy
  6. The sudden death of the fish.

How quickly can Ich kill a fish?

If the fish are not treated or if the treatment is delayed for an extended period, the disease is likely to result in their demise. The ich infection is progressing rapidly, and fish may die within a few days. Furthermore, the parasite spreads throughout the aquarium and infects other fish. All will be lost if you don't start treating your aquarium. Do you see signs of disease in your aquarium? Don't wait!

What causes ich in fish?

  1. The most common cause of ich is the introduction of infected fish into the fish tank.
  2. It's possible to infect the aquarium if you use water from another tank.
  3. If you purchase used equipment, disinfect it before putting it into the aquarium. If you don't prepare this equipment, your aquarium could be exposed to ich.
  4. You need to know that water quality is also crucial. It affects the fish immune system. Aquarium fish living in unclean water are much more susceptible to all kinds of diseases. Moreover, the treatment of fish will be much more difficult or even impossible. Therefore, we recommend taking care of water quality and frequent water changes.

Treatment and prevent ich

Prevent ich

You should follow this sentence: "Prevention is better than cure." Your fish will thank you. Don't put them at unnecessary risk. Here are some suggestions on how to prevent not only ich, but also other fish diseases:

  1. The first and the most important thing is quarantine new fish. I'm sure you want to see a new fish in your beautiful aquarium as soon as possible, but the smartest thing to do is to put every new fish in a quarantine tank. Do the same with new plants.
    The quarantine time for fish should be 4 to 6 weeks. In the case of plants, 2–3 weeks.
    To make sure the fish is in good shape, you can keep it for a bit longer, as the ich isn't the only disease that can be found in aquariums. The quarantine process helps protect the aquarium from diseases and parasites.
    Raising the temperature will speed up the process of quarantine, but may increase stress on the fish. Their immunity will be diminished as a result.
  2. The next point is also essential. Avoid increasing stress to your fish, this can lead to serious problems, such as weakened immunity. That's why it's so important to maintain proper water parameters!
    The main factors that increase stress:
  • improper diet, poor quality fish food
  • too much or too little water flow
  • poorly adjusted water parameters
  1. Do not use accessories you have collected in the natural environment. These things might contain various types of parasites and could affect water parameters.

Ich treatment

If you notice the first symptoms of the disease, you need to act quickly. Unfortunately, the parasite will not be able to leave the aquarium. Furthermore, it will quickly multiply and spread to other fish.

First of all, the sick fish should be quarantined, separated from the healthy fish. Then thoroughly disinfect the aquarium where the parasites have appeared. You should also consult a veterinarian who specializes in aquarium fish and follow his recommendations.

Freshwater aquariums

  1. First, you can try increasing the temperature in the infected aquarium. This should be done slowly and carefully. It is worth noting that such a solution may increase the stress of the fish. Find out in advance if your fish can survive at higher temperatures. Elevated temperature causes the death of all stages of the parasite.
  2. Another natural method is to increase the salinity of the aquarium water by adding aquarium salt. There should be no more than 10–15 grams of salt per 10 liters of water. You should change the salt water after 3–4 days to freshwater. Sadly, this approach, like the previous one, is not suitable for all fish, as some species are incapable of thriving in waters with higher salinity.
  3. There are also substances that can help get rid of parasites.
  • Malachite green
  • Formalin
  • Methylene blue
  • Potassium permanganate

Note that these substances are toxic in high concentrations. When removing parasites and killing ich, they can also destroy the aquarium's biology. Self-dosing is not recommended for beginners. When using them, follow the manufacturer's recommendations and consult a specialist.

To simplify use, we created AF Purify, which contains malachite green and methylene blue in a safe concentration. This product is designed for freshwater fish and aquariums with ich problems. Furthermore, AF Purify will improve the immunity of your friends. We recommend using it only in quarantine tanks, as it may stain the decoration.

Marine Aquarium

  1. For Cryptocaryon irritans, a proven method is the use of copper-based medicines. Please note that copper is toxic to corals and invertebrates. Before applying medication, place the host fish in a quarantine tank. Dose according to the manufacturer's recommendations. It is also a good idea to use nutrient-rich foods to help the fish survive.
  2. The disease isn't harmful to corals, so you can simply remove all the fish from the infected aquarium and keep them in a quarantined tank. The parasite should die of starvation. This period can last from 4 to 8 weeks.
  3. To help with these solutions, you can use UV sterilizers. They are not as effective as the previous methods, but they are worth mentioning