You have just fed your fish and are admiring their lovely colours and movements and then you notice tiny white spots on them. Don’t freak out, these little spots which resemble sugar or salt crystals sprinkled on your fish are actually a tiny parasite protozoan called Ichthyophthirius multifiliis, or “ich” for short, and is very contagious.
The parasites spend a portion of their life cycle embedded beneath the skin of the fish where they feed off of the body tissue. You may notice your fishes fins are clamped and that they flick themselves on the bottom of the aquarium to try to remove the parasites. Sometimes you will notice that the fishes fins are clamped even before you see any white spots. This can indicate that the spots are about to appear. These white spots are embedded beneath the slime coating and are not easily removed by the fish. Adults emerge from these cysts and fall to the floor of the aquarium where they multiply inside a protective capsule. The capsule eventually bursts, releasing hundreds of free-swimming infectious parasites which attach themselves to new hosts, and the cycle begins again.
An Ich outbreak can sometimes occur when a new fish has just been introduced into an aquarium and it’s immune defenses are weakened from the stress of transport. Ich can also be introduced when the temperature of the aquarium drops dramatically from a power outage or a sudden change in climate, or simply just because. There are many schools of thought regarding where these little creatures come from. Some aquarists believe ich can be latently present in the aquarium for a long time. In any case it is important to get rid of them.
1. Remove any carbon in the filter before beginning any treatment as it will render the medication useless.
2. Raise the temperature of the aquarium by 2 degrees C or 4 degrees F. This speeds up the life cycle of the parasite so it can be destroyed quicker.
3. Add aquarium salt to the water. The salt acts as a disinfectant by slowly releasing oxygen into the water and encourages parasites to detach from the skin of the fish. Note that fish vary in their tolerance of salt, and for more sensitive soft-water species, we recommend using 3-4 tsp per gallon maximum. Higher salt levels may also affect plant growth.
4. Add a medication to the water. Always read the label of the medication carefully and follow the manufacturers instructions. Some fish like Clown Loaches, Irridescent Sharks, Elephant Nose, Stingrays and some varieties of Tetras are sensitive to many medications and it is advisable to only use a half dose. There are many different kinds of medications on the market that use copper to kill the ich parasite. Copper is very effective however it can affect plant growth and sometimes kill certain plant species.
Due to the life cycle of ich the whole tank must be treated in order to kill all the parasites which are not attached to fish (it is not appropriate to only treat affected fish in a separate isolation tank). Once treatment is complete do a 1/3 water change, add new carbon to your filter, lower the temperature back to normal and feed your fish a high quality fish food like Sera GVG Mix. This is one of the best fish foods in the market today. It will help the fish recover from the parasite by growing new healthy skin and scales.
If you have added salt to the water during treatment it is very important to continue with water changes of 1/3 for the next 3 weeks to remove all of the salt that has been added to the aquarium. Salt does not evaporate so it has to be removed with the water.