Sudden change in temperature and/or poor water conditions can lead to White Spot Disease. Knowing the lifecycle of the germ that causes this disease will help treat the affected fish. 

Ichthyophthirius Multifilis

White spot disease is actually a protozoan parasite. These parasites attach all over the fish’s body and leeches off nutrients from the fish. You might notice white dots on the fish’s body or its fins. These small spots are tiny parasites. 

They reproduce quickly so once one or two fish catches this disease, it spreads very quickly to the whole tank. Therefore, if you found one fish that has been affected, it is best to treat the whole tank. If you just treat the affected fish by putting it in quarantine, the eggs or larvae of the parasite are left behind and the problem will persist. 

This disease is one that most novice fishkeepers commonly face. Fortunately, it is relatively easy to treat. 

Understanding the lifecycle of Ick, White spot, disease

The higher the temperature, the faster the cycle (At 87 degrees temperature, around 3-4 days)

Materials

Tank heater

White spot medication (or sea salt) 

Treating using white spot medication

First off, it is very important to discover the disease early on. 

When found too late, fish can die due to stress while being treated. In this case, the dead fish must be removed from the tank as soon as possible. 

The initial treatment for any disease is water testing. If you do not know the water conditions, the treatment steps below are meaningless. For water testing, check out the article below. 

https://www.aquadesk.com/articles/testing-fish-tank-water-parameters-ammonia-nitrite-nitrate-ph

First, add the medication based on its instruction and raise the tank’s temperature by 5 degrees every 6 hours until the final temperature is 87 degrees. It must be done gradually because sudden rise in temperature, for example from 72 degrees to 87 degrees, can cause the fish stress and ultimately death. 

Raise the temperature 5 degrees before going to work, then 5 degrees after work, etc.

Raising the temperature will accelerate the parasite life cycle causing the parasites to detach from the affected fish and split, making them into larvae stage where they are treatable with medicine. The medicine has little effect on the adult parasites. 

After 4 days, perform a 30% water change. At the time of water change, use a siphon to thoroughly clean the substrate. This is to get rid of any parasite bodies or eggs that are on the floor. When water change is done, add another dose of medicine. It might differ by brands or type of medication, but it is best to add the same amount as before and not based on the amount of water you’ve drained out.  

After doing this procedure 3 times, around 2 weeks (12 days) should have passed. 

At this time, stop medicating, keep the temperature at the same level, and observe. If white spots occur again, repeat the medicating steps above.

After 2 weeks, if everything is back to normal, decrease the temperature the same way you increased it.

I recommend taking longer to decrease the temperature, for example, decrease 6 degrees every 3 days.



Treating using sea salt

Treatment using salt or sea salt is the same as treatment with medicine. Instead of medication, you will be using sea salt. However, when re-medicating after a water change, it is important to add salt for the calculated amount of new water only. 

Some fish and living things (pleco, loaches, water plants) are sensitive to salt so make sure your fish is ok before using salt as a treatment method. 

Treating with salt works by osmosis. Most freshwater fish maintains a 0.6% salinity. So a little bit of salt does not hugely affect the fish. On the other hand, the parasites have less salinity so when they are exposed to salt water, water is excreted from their body (osmosis) and they shrivel up and die. 

Reason for most outbreak

Rapid change in temperature in a short amount of time (7 degrees or more)

Adding a new fish without quarantine

Adding a new plant without quarantine

Water conditions deteriorate due to feeding and failure to manage water quality

After treatment

After treatment, I recommend sterilizing all of the equipment used in the affected tank, such as fish nets and siphons. This is to make sure any parasites that were on the equipment dies. You can soak it in a high salinity water or sterilize in a hot water bath. Pick the method that is best suitable for your equipment. I also recommend letting the equipment dry in direct sunlight.  

Most important point: Most diseases start with water condition problems. 

Also, most water problems happen due to overfeeding or water decomposition.

https://www.aquadesk.com/articles/the-beauty-of-fasting-overfeeding-underfeeding

Water spot disease can arise again if you do not know the underlying cause.

It is correct to assume that there are various germs and parasites, including ick, white spot disease, living in most tanks. When the water conditions deteriorate and water cycle breaks, the fish’s immune system is compromised and the germs and parasites propagate. 

All solutions start from correct water diagnosis. I hope the links below help you. 

https://www.aquadesk.com/articles/testing-fish-tank-water-parameters-ammonia-nitrite-nitrate-ph

https://www.aquadesk.com/articles/the-importance-of-observing-your-fish-5-minutes-everyday

https://www.aquadesk.com/articles/making-correct-analysis-before-managing-water-quality