How to Cure White Spot (ich) in Tropical Fish

Distinguishing white spot disease in freshwater fish and saltwater fish. The disease develops in both saltwater and freshwater fish in the same way but has different cycle lengths and requires different treatments. In both aquatic environments, this single-celled parasite attaches to fish for survival. In the wild, ich rarely becomes a problem because the parasites are unlikely to find a host. Even if it is attached, the parasite will eventually come off and the wound on the fish will heal on its own. In contrast, when living in a closed tank environment, ich parasites can easily attach to fish, multiply and infect, eventually killing all fish in the tank.

• In freshwater environments, the ich parasite is known as ichthyophthiriasis . ^[1]
• In saltwater environments, ich are called cryptocaryon irritans and are often confused with other parasites that cause white spots. Saltwater ich have a longer reproductive cycle than freshwater ich but only have 12-18 hours to find a host before dying, unlike freshwater ich, which can live up to 48 hours outside of a host.

Understand that stress is a risk factor for infection. Ich is quite common, so most fish have good immunity to it. However, stress can suppress the fish’s immune system, and when this is the case, this parasite will be most rampant. The following factors can cause stress:

• Inappropriate temperature and poor quality water
• Other creatures living in the tank
• New creature arrived
• Improper diet
• How to transport and handle fish during the move
• The indoor environment, especially the house with a lot of loud noises, door knocking, door shaking, people or objects constantly moving around the aquarium

Learn to recognize the symptoms of ich. Disease symptoms can manifest in fish bodies and their behavior. The most obvious sign of ich disease is the appearance of small white spots like salt particles, hence the name white spot disease. ^[2] Common signs of ich are:

• White spots are present on the body and gills of the fish. These spots can stick together to form white patches. Sometimes, ich only appear on the gills of fish.
• Excessive movement. The fish may rub against plants or rocks in the tank more to try to dislodge the parasites or due to itching.
• Fin closed. Fish always close their fins close to themselves instead of spreading freely. ^[3]
• Heavy breathing. If the fish come to the surface to take a bite or often hang around near the filter in the tank, they are probably suffering from a lack of oxygen. The ich parasite clings to the gills of fish, making it difficult for the fish to absorb oxygen in the water.
• Anorexia. If the fish doesn’t eat or spits out the food, it’s a sign of stress and illness.
• Hiding behavior. Animals often hide when they feel sick, and any change in behavior is often a sign of stress or illness. Fish may hide in decorative objects or may not be as active as usual.

Treat fish when parasites are most vulnerable. Ichs can only be destroyed when they are not attached to the fish, which happens when fully mature parasites leave the body of the fish to multiply themselves into many infected units of the ich parasite. When parasites attach to fish, they will be protected from chemicals, and then the medicine will not work. The ich parasite goes through several life cycle stages:

• Trophont stage: During this stage, ich parasites can be seen on the fish. They burrow under the fish’s mucus and form a protective capsule that blocks chemicals and neutralizes drugs. In a typical aquarium with a temperature of 24 – 27ºC, the trophont stage, also known as the parasitic stage, will take place for several days before the cysts have fully developed and left the fish.
• Tomont or tomite stage: During this stage, treatment can be effective. Parasites in this period, also called tomont, will float for many hours in the water until they attach themselves to a plant or another surface. Once they have found something to cling to, they will begin to rapidly divide or multiply within the capsule. A few days later, these cysts will burst, and the newly formed organisms will begin to swim in search of a new host. Freshwater tomont can multiply very quickly in 8 days, while saltwater tomont can take 3 to 28 days to divide.
• Thermonts or swarmer stage: Freshwater swamers will have to find a host (fish) within 48 hours or they will die, while saltwater swamers only have 12-18 hours to find a host. So, one way to completely get rid of ich in an aquarium is to leave the tank empty for 1 or 2 weeks.

Observe the temperature in the tank. High temperatures will accelerate the life cycle of the parasite. Aquariums with higher water temperatures will end the life cycle of parasites in a few days, while low temperatures will prolong their life cycle for weeks.

• Never increase the temperature in the water suddenly. This can cause fish stress and some fish cannot tolerate high temperatures.
• Most tropical fish can tolerate temperatures up to about 30ºC. You should always consult a tropical fish specialist to find out what temperature they can tolerate.