The Dreaded White Spot: Treating and Preventing Ich

fish with ichIf you keep fish, you've almost certainly heard of Ichthyophthirius Multifillis...or, more simply, Ich. Though many amateur aquarists misdiagnose their afflicted fish with Ich because of the presence of any kind of white spot, once your fish actually have the real disease it's unmistakable.

Ich is a parasite that first appears as a bunch of small white cysts on the fish's skin, generally concentrated around the gills and fins. These spots are "clean" and compact, looking much like someone sprinkled salt over your fish. If this does not describe the spots on your fish, it's not Ich...fin rot, columnaris and a multitude of other parasites and infections have some form of white or grey spotting. Ich can be deadly to the fish, though surprisingly most fish that have Ich do not die because of the parasites. Instead, most die from secondary infections from having less-than-pristine water or even from the harsh medications meant to treat Ich.

How do the fish get Ich? Sometimes it's from infected new fish, sometimes there are even parasites already living in the aquarium that you never know about until conditions are right for them to infect the fish. So what do you do? keep your fish as healthy as humanly possible. If a fish is active with a strong immune system and a healthy slime coat, their chances of being infected are minimal. In the event that such a healthy fish does get infected, they have a very good chance of fighting off the parasite and avoiding secondary infections.

The first step to keeping fish healthy is to feed them a high-quality, varied diet. The food sold at most pet stores do not qualify as high-quality, though if it's all that's available it will do for maintenance care as long as they have some dietary variation. It's easy to cultivate live food such as brine shrimp, vinegar eels, mosquito larvae or grindal worms to add necessary protein and variety into the diet. There are plenty of online sources of healthy fish food as well as recipes for creating your own top-of-the-line food for your finned pets.

The next - and most important - step to keeping fish healthy and preventing secondary infections in afflicted fish is to have a clean aquarium. Just because the water is clear, doesn't mean it's clean or healthy. A healthy tank will require a partial water change at least every two weeks, depending on stocking levels (though water maintenance products such as EcoBio-Stones can significantly reduce these), and nitrate levels need to be kept below 20ppm. Most books and sites will recommend no more than 40ppm nitrates, however some types of fish and invertebrates such as snails, shrimp, smaller tetras and angels do not like the higher levels, so it's always best to err on the side of caution.

Water changes help keep the parameters within acceptable limits, help remove excess organic material such as waste and uneaten food, and also replenish required minerals in the water that the fish use up over time. If you prefer not to do as many water changes or are physically unable to, there are alternatives to doing so many. My favorite is the aforementioned EcoBio-Stone, which is a water maintenance product that introduces beneficial bacteria into the aquarium (which keeps the biological filter healthy) and slowly leaches necessary minerals into the water to keep fish healthy. You'll still need to do a gravel vacuum occasionally to remove excess organic material or stir your substrate to get rid of potentially harmful gas pockets and bring the organic material up where your mechanical filter can remove it from the aquarium.

Finally, if your fish do get Ich, avoid commercial medications if possible. Most Ich medications contain Malachite Green, a chemical that is very toxic in concentrated amounts and is often used as a dye. This is very effective at killing parasites, but is also very hard on the fish and you run a risk of killing them too. Invertebrates and plants are at special risk with these products. Instead, make sure your water parameters are ideal (this may require a partial water change) and then treat with aquarium salt and a topical antibiotic such as Melafix. Exactly how much of each of these will depend on the size of your tank and whether you have invertebrates or scale-less fish such as tetras. While any medication is being used you should remove activated carbon from the filter. If you have EcoBio-Stone, vacation food, calcium blocks or any other leave-in or time-released products they will need to be removed before treating the aquarium. Keep EcoBio-Stone in de-chlorinated water if you'd like to avoid any extra re-starting time.

If you wish to decrease treatment time, raising the temperature will speed up the life cycle of the parasites so they can be killed sooner, but be careful if you decide to do this. Many sources suggest heating the water to 80F which is great for tetras, guppies and the like, but the safe temperature varies widely for each fish. The temperature of the water determines how much dissolved oxygen the water can hold, so it's safe to heat the water to the upper comfortable limit for each fish but not much warmer. This means that for many hardy community fish 80F works well, but for some goldfish or mosquito fish it shouldn't be any warmer than 75F while some types of cichlids may be able to handle 83F without a problem. Do some research on all the species of fish in your aquarium to determine how much you can safely heat the water.

Bear in mind that the salt will kill the parasites, but it cannot harm them while they are inside the fish. It can take up to two weeks for the cysts to burst and another couple of weeks after that for all of them to die. The aquarium should remain treated for the entire time, about 4-5 weeks. The antibiotic helps prevent deadly secondary infections. After the treatment phase is over the salt and medication may be removed by water changes or with activated carbon; then you just need to examine your feeding and maintenance habits to keep the infestation from happening again.

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