WHAT IS ICH?
Ich (short for Ichthyophthirius) or Whitespot is a parasitic protozoan that infects fresh, brackish and saltwater fishes. It is identified by small white spots that appear on the fish's body & fins.
There are several stages to this parasite's lifecycle and it must be noted that the parasite can only be killed during its free swimming stage. That is when the parasite is swimming around in the water looking for a new host.
Stage 1: The white dots on the fish. The parasite has attached itself to a fish and is feeding off it. The parasite has a white case that is glued to the fish and is protecting the parasite from everything.
Stage 2: The parasite has gorged itself on fish blood and drops off the fish and sinks to the substrate. When the parasite detaches from the host fish, it leaves a small wound and the fish's immune system patches up the wound leaving a small scab. The white spots disappear from the fish because the parasites are now on the bottom of the tank dividing/ reproducing inside their little white case.
Stage 3: The white case with the parasites inside, ruptures open and releases hundreds of new parasites that swim around the aquarium looking for a new host to attach to. This is the only time you can kill this parasite, while it is swimming around looking for a new host. Once the parasite finds a new host and produces its little white case, you cannot kill it. If the parasite is not killed during this free swimming stage there will be a lot more white spots on the fish.
Fish die from this parasite because they can't breath. The parasites affect any part of the fish they can attach to, including the gills. When the parasites drop off the fish they leave a small wound that becomes a scab. One little scab is not an issue, but when the fish has 500 little scabs on their gills, it becomes very difficult for them to breath. The parasites damage the gills and cause scabs and scar tissue and the fish suffocate. Large numbers of parasites can also cover the gills preventing the fish from absorbing oxygen from the water.
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TREATMENT
Treatment can range from Sulphur based medications (triple sulpha), Malachite Green based medications, Copper based medications, heat treatment, and moving the fish. Malachite Green based medications are the most commonly used and are available from any petshop.
*NB* Malachite Green is carcinogenic (causes cancer), so you should try to avoid coming in contact with this substance and wash your hands and arms with soapy water after handling medications containing this chemical. In fact you should wash your hands and arms after handling any fish medication or using any water test kits, or just working in the tank.
*NB* Keep all medications away from children and animals. Try to keep them in a cool dry place and check expiry dates when purchasing them.
Heat Treatment
The parasite does not like heat and raising the temperature of the water to 30 degrees Celsius for 2 weeks will usually kill off the parasite. If the water temperature is below 24C then the temperature should be raised to 30C slowly, over a 24-48 hour period.
*NB* If you are keeping coldwater fishes do not use heat treatment.
When using heat treatment you need to increase surface turbulence because warm water holds less oxygen than cool water.
It is also a good idea to do a 80-90% water change and gravel clean the substrate, and clean the filter before treating the fish with any medications or heat. The water change and gravel clean will dilute the number of free swimming parasites in the water and cysts in the substrate, as well as removing most of the rotting organic matter that is in the gravel and filter. This allows medications to work more effectively and focus on the harmful pathogens rather than the bacteria feeding on the gunk in the gravel.
If you don't want to use heat treatment or can't because you have coldwater fishes, and you are unable to get medication for a few days, you can limit the number of free swimming parasites in a tank just by doing big water changes and gravel cleaning the substrate. You do a 80-90% water change and complete gravel clean each day until you get medication. The big water changes dilute the number of pathogens in the water and that reduces the number of parasites that can infect the fish.
*NB* Any new water being added to the aquarium must be free of chlorine/ chloramine before it is added to the tank.
*NB* Big water changes and gravel cleaning alone will not cure the disease. It is simply to buy you some time until you can get some medication to kill off the parasites.
Moving Fish
This is something I do with marine fishes if they are in a coral tank or aquarium with invertebrates. Basically we move the fish into a clean container of water every day for a week. The parasites on the fish drop off after a few days at 26C, and sink to the bottom of the container. Each day you move the fish out of that container and into a clean container with new water. There are no free swimming parasites in the new container of water so the fish cannot be reinfected. And by moving the fish into a new container each day, you move them away from the parasites that have dropped off them. Eventually all the parasites have fallen off the fish and the fish are free of the disease.
A heater (if required), thermometer and an airstone should be added to the container of water to help maximise oxygen levels and keep the water warm for the fish. The heater, thermometer, airstone and attached airline/s should be cleaned and disinfected before being used in another container. As should any nets used to transfer the fish from one container to another.
Depending on water temperature in the main aquarium, you can usually put the fish back into their tank after 1 week. However, I prefer to keep them out for 2 weeks. The free swimming parasites cannot live more than 48 hours without a host fish. And it can take a week for all the cysts in the substrate to open. Keeping fish out of the tank for 2 weeks guarantees there will be no parasites left alive in it.
Corals and shrimp are not affected by Ichthyophthirius.
You only need 2 or 3 containers for this. Once the fish have been moved out of one container, you wash it out with hot soapy water and then give it a wipe down with bleach. Leave the bleach for 15 minutes and then wash the container out again to remove the bleach. Allow the container to dry completely and it is ready for use.
If you use aquariums for this, only leave the bleach in the aquarium for 5 minutes because bleach damages the silicon glue that holds the glass together. I prefer to use plastic storage containers for this purpose because the plastic is unaffected by the bleach.
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There are new strains of this disease that have developed a resistance to most of the common medications that contain Malachite Green and Sulphur, and some parasites have developed a tolerance for high temperatures. In these cases you can use the moving technique or try to find a medication with Praziquantel in. Praziquantel is used to treat cats & dogs for tapeworm, but it also works on fish. And work done on it in 2005-2006 by associates at a petshop in Perth, showed it killed Ichthyophthirius.
If none of the above treatments work, you can use Copper based medications. The parasite has not developed a resistance to copper and it will kill them. However, you CANNOT use copper in an aquarium with any invertebrates (shrimp, crabs, snails, corals, anemones, starfish, octopus, etc). Copper will kill these organisms as well as the parasites.
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There are rumours that this parasite is found in all aquariums and all untreated water. That is false. The parasite has to be introduced into a water body, where it must find a suitable host within 48 hours or it will die. The only way for this disease to get into your home aquarium is through introduction of the disease. You have to bring this disease into your aquarium either on a new fish, new plant or other object from a contaminated tank, or in some water that has the free swimming parasites in it.
