Ich, also known as White Spot Disease, is the most frequent parasite found in tropical fish aquariums. Most aquarists face this unwanted guest at least once in their time and agree it is responsible for more deaths than any other infection among fish.
Ich is the abbreviation for Ichthyophthirius, a genus belonging to the protozoan causing the infection. These protozoans are constantly present in the water in small numbers and are usually tolerable, but can wreak havoc when fish become stressed by sudden changes in the aquarium.
The protozoa gain advantage of the fish’s weaker immune system and attach to the slime coat of the fish, creating small white spots, sometimes even grouped to form larger patches.
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How to prevent Ich
It is considered almost impossible to completely eradicate Ich from your aquarium. Small amounts will always be present even in the most well maintained tanks, but healthy fish will always be able to live alongside these germs and tolerate them, just as a healthy person’s immune system can handle a few germs in the air.
Of course, even the healthier specimens may fall ill when placed in an overcrowded aquarium together with infected ones, especially when sufficient water changes are not performed.
As a cautionary act, it is very important to quarantine new fish for about two or three weeks before placing them in the main tank to observe any signs of illness and treat them individually.
Stress is another factor affecting fish immunity and can cause them to become ill. Fish can be stressed when new fish are added to the aquarium or water temperature, pH, or oxygen levels suddenly change.
This is why all changes must be done gradually, to allow fish to adapt during the process.
Last, but not least, weakened fish may be the best breeding ground for parasites. Always make sure to keep sick or recovering fish in a separate tank and place them back in the main one when they are fully recovered to stop the spread of the infection.
How to treat Ich
Chemical substances may be too harsh on already ill fish and if not dosed properly can harm them even more. This is why most aquarists prefer to rely on more natural methods, as well as slight changes in the environment.
It is imperative to kill the parasite in its swimming state, as while it stays inside its cyst attached to the fish’s slime coat, it’s very hard to remove.
Raising the water temperature
If all the fish in the tank can handle temperatures up to 86-89° Fahrenheit (30-32° Celsius), gently rise the water temperature by 1 degree every 1-2 hours.
The Ich cannot withstand such warm water and will perish in about two weeks. If the fish can tolerate it, raise the temperature to 89° Fahrenheit for 3-4 days and then leave it at 86° for another 10 days.
Increase aeration
Oxygen levels decrease in warmer water and can also lead to fish suffocation. As the Ich already inhibits the fish’s ability to breathe, extra oxygen must be added to the tank, which can be done by decreasing the water level.
The filtered water hitting the surface will produce more oxygen bubbles, adding more air stones or using bubble disks will also help.
Adding salt to the water
Aquarium salt helps fish recover their natural slime coat and thus increases resistance to infections. It also disrupts the Ich developing cycle. Combined with increased water temperature, it can be a very effective cure to Ich infections.
Always remember to only use aquarium salt, as table salt usually contains iodine. Medication should not be used together with salt and heat, as this combination consumes the oxygen in the tank.
Only add salt to a small amount of water and do frequent water changes. If all the fish are healed and treatment is over, continue with water changes, but do not add salt anymore.
Of course, if the parasite it very strong and these methods just don’t seem to work, you have to purchase stronger medicine from your local pet store and treat the tank.
One good thing is fish previously infected that managed to cure themselves become resistant to the Ich and will not be infected again.
Always keep in mind prevention is the best cure and keeping healthy fish by constantly monitoring the water parameters reduces the chances of the fish becoming ill.
Also, keep newly purchased or young fish in quarantine tanks before introducing them to your established aquarium.