|Understanding and Treating Ich
or White Spot
|by Shelie Wittig ( Fishgal )|
This is a common parasite which most aquarists eventually encounter. Even if you follow quarantine procedures you may at some point acquire an infected fish, which should be treated before being introduced into your main aquarium. The good news is that if handled correctly, this disease can be easily and permanently eliminated.
What Is It?:
The scientific name for this nuisance is Ichthyophthirius multifiliis, or “ich/ick” for short. It is the largest known ciliated protozoan found on fishes. It appears on the body and fins as tiny white dots resembling grains of salt; hence the other nickname, “white spot disease.” These white spots may join together to form white patches. Other signs of infestation can include excessive flashing (rubbing against the substrate or decorations), labored breathing, clamped fins, loss of appetite, lethargic and/or reclusive behavior, and hovering near filter returns. Keep in mind, however, that all of these symptoms are common with fish in distress and do not point directly to Ich. As a matter of fact, flashing often occurs after routine water changes due simply to a fluctuation in general hardness.
Ich has three life stages, which are important to understand for proper diagnosis and treatment.
Left untreated, Ich is almost certainly fatal. Infected fish are weakened by the ever growing number of parasites feeding on them. Secondary bacteria and fungi attack more easily. Trophonts on the gills eventually restrict oxygen flow and respiration is hindered. The ailing fish will ultimately succumb either to the infestation itself or a secondary condition.
How Do I Prevent It?:
I came into the research phase of this article with certainmisconceptions about this parasite. It is a commonly held belief that the Ichthyophthirius organism is always present in your aquarium and needs only the right opportunity, such as stress resulting in a weakened immune function, to attack your fish. Surprisingly, I found no scientific data to support that claim. Credible sources state that there is no long-term dormant stage this parasite can exist in. While its lifecycle is longer at low temperatures (like that of an outdoor pond in a cooler climate), at average home aquarium temperatures this parasite would likely complete a lifecycle in less than a week. Considering that a single organism produces hundreds (if not thousands) of offspring, the logical question is “where would they all go?” Dr. Peter Burgess, writing for Practical Fishkeeping magazine (who also co-authored the book entitled A to Z of Tropical Fish Diseases and Health Problems), refers to the dormant concept as “rubbish.”
The proliferation of this myth could be due to the fact that it is possible for a strong, healthy fish to resist severe infestations, especially if it was infected previously and developed some resistance. While the organisms attach easily to the gills of most fish (where they cannot be seen), the body may be sufficiently protected by a tougher mucus coating. Such a fish could serve as an asymptomatic carrier; potentially hosting many lifecycles without showing any visible signs. When introduced to a new tank it brings the parasite with it. Scaleless fish such as loaches and catfish often show symptoms first, but most likely every fish in the tank will eventually be infected; if not visibly on the body, on the gills at the very least.
It stands to reason that a stressed fish with a weakened immune function is an easy host, but only if the parasite is present in the tank to begin with. That brings us back to how to prevent it, now that we know it is not lurking in every aquarium waiting to strike. Here are few guidelines:
How Do I Treat It?:
There are many over-the-counter medications for ich. They all boil down to a few common ingredients, each of which has a downside. In addition, Ich outbreaks often accompany cycling problems and it is difficult to keep up with frequent small water changes (to minimize ammonia and nitrite levels) while dosing with a medication that advises not to do any water changes during treatment. With that said, I’ll start by recommending my first two choices for treatment, which are more “natural” (or at least less “chemical”) and should be easier on your fish, your biological filter, and your wallet.
There are two schools of thought regarding raising the temperature of the water to treat ich.
The adjusted temperature should be maintained for approximately 10 days, or a minimum of 3 days after all signs of the parasite have disappeared. Do not discontinue treatment when the spots go away. This is critical, because we know that they are visible only as a trophont on the body of the host, and not during the reproductive or free-swimming stage. We also know that trophonts on the gills are impossible to see.
One last note on raised temperature treatment: If you follow the directions here thoroughly and have a subsequent outbreak without having added new fish or plants, you may need to try a different approach. It is possible to encounter a resistant strain of ichthyophthirius, as there have been rare instances recorded where the organism survived at 92ºF!
Salt is frequently recommended for treating a myriad of fish diseases, especially those involving external protozoa and fungi.
What kind of salt? We are not talking about “marine salt” or “cichlid salt” (both of which typically contain a blend of mineral salts and trace elements specially formulated for aquarium use to simulate ocean or rift lake water chemistry). You want sodium chloride (NaCl). “Aquarium salt” is the most widely used form because it does not contain the iodine or anti-caking agents that table salt does. I will say, however, that several credible sources assert that the minute amount of additives in table salt are harmless. Robert T. Ricketts, writing for AquaSource online magazine, puts it best with “any water-living vertebrate would be pickled in brine well before toxic concentrations of iodine could be reached.” Still, others offer strong warnings about the dangers of iodine and prussiate of soda (an anti-caking agent) and suggest “canning salt” as a cheaper alternative to aquarium salt. Make your own choice, but since I’ve heard only warnings and no actual accounts of fish death by table salt, I assume it’s most likely the ‘better safe than sorry’ principle at work here. “Sea salt” is another option, and is generally available in nutrition stores because it is considered a more “natural” form of salt. It does not contain iodine, but may have anti-caking agents. I have used it in my aquariums without incident.
Can my fish handle salt? I wrote this article with African rift lake cichlids in mind, and I have successfully exposed my Malawi haps and clown loaches to a salt treatment without any problems. But these fish are accustomed to fairly hard water with a high pH. It is my understanding that species preferring soft water will not tolerate salt as well. If you keep soft water fish, please do your homework before proceeding with salt.
How much? I visited websites and read articles on treating Ich in generic freshwater fish, food fish, guppies, loaches, and African rift lake cichlids to name a few. I encountered dosage recommendations ranging from about 1.75 tablespoons to 6 tablespoons salt per 5 gallons of water. One rift lake cichlid importer/breeder uses “1 handful” of salt per 5 gallons of water. I concluded that my fish can probably tolerate more salt than I think, at least on a short-term basis. Based on everything that I’ve read to date, I would feel comfortable adding 2-3 tablespoons salt per 5 gallons if I were also using the high temperature treatment outlined above. If I were using salt alone, I would work my way up to 4-5 tablespoons per 5 gallons. We don’t want to skimp on our treatment if we hope to permanently eliminate this pest. Salt should be added slowly over the course of 24-48 hours or so (always dissolve in a small container of tank water first). Keep a close eye on your fish and perform an immediate water change if they show any additional signs of stress (beyond what the Ich is already causing).
How long? The salt bath should be maintained for approximately 10 days, or for at least 3 days after any visible signs of Ich can be detected. Do not discontinue treatment when the spots go away. If you use a higher dosage of salt, watch the duration more closely. One article (on guppies) specifically stated not to leave the fish in salt longer than ten days, but their dosage recommendation was on the high end at 5 tablespoons per 5 gallons.
What else should I do? The salt bath can be used on its own, or in conjunction with a temperature adjustment as described in the section above. A water change can be performed during the salt treatment (but is not necessary unless nitrates are creeping up to an undesirable level). Be sure to salt the replacement water accordingly to maintain salinity. Gravel vacuuming is also helpful to remove as many tomonts as possible before they can release offspring. Again, this is not absolutely necessary since the salt should destroy the free-swimming thermonts upon their release.
At the end of the treatment, do several large (40-50%) water changes with dechlorinated unsalted water to reduce the salinity to normal.
One last note on salt treatments: If you follow the directions here thoroughly and have a subsequent outbreak without having added new fish or plants, you may need to try a different approach. It is possible to encounter a resistant strain of ichthyophthirius, as there have been rare instances recorded where the organism survived in water salted at more than 5 tablespoons per 5 gallons.
As stated previously, there are many products available for treating ich. Whatever you choose, be sure to:
Copper-based medications are commonly recommended for treating ich. Some brand names include CopperSafe® by Mardel,General Cure® by Aquarium Pharmaceuticals, and Aquari-Sol®. Look for the active ingredient “copper sulfate” or “soluble copper salts.” Copper does not stain and is highly recommended by some aquarists. It does have drawbacks, however. It causes oxygen concentration to drop, it is toxic to snails and invertebrates, it may not be tolerated well by scaleless fish and plants, and like any chemical, it can certainly be toxic to your fish especially if dosed incorrectly. Apparently the toxicity increases as total alkalinity (KH) decreases. This would suggest that copper-based meds may be better suited for use with African rift lake cichlids than with soft water fish from low pH/KH conditions. But beware; if you should have a drop in your pH while using copper your fish could perish.
Potassium Permanganate has been suggested as an alternative to copper for treating ich, especially in soft water fish. It is primarily used in ponds, and is not in my opinion the best choice for aquarium use. It most certainly is not for the beginner. It can be purchased under its chemical name, or found as the active ingredient in products such as Flukes Control® by Aquatronics. As with so many chemicals, there’s a fine line between calling it a wonder drug and a lethal substance. It is not really a medication but an oxidizing agent that reacts with organic material, resulting in the destruction of external bacteria, fungus and parasites. For that reason, it is considerably less effective with excessive nitrates present, because its oxidizing power is “used up” on the dissolved organics in the water and is consequently not effective against the target pathogen. It is often used by retailers as a dip for incoming plants, to eliminate snails and their eggs. It is toxic in high doses, especially in high pH water; there are better choices for treating African rift lake cichlids. It is not safe for eggs and fry, and excessive treatments can cause gill damage in adults. It will damage your biological filter, kill algae, and reduce oxygen concentration in the water; strong aeration and water movement is critical. It can be tough on live plants and catfish, and should not be combined with any other chemicals – especially Formalin. It can burn your skin and eyes, and will stain your hands and clothing brown; gloves are recommended. It cannot be removed with carbon like other meds; it is neutralized with hydrogen peroxide but I don’t know exactly how that is accomplished safely in the aquarium. Again… this is for the advanced fishkeeper.
Formalin is a form of formaldehyde and is often used by fish farmers and home aquarists to treat ich. It can be purchased under its chemical name, or found as the active ingredient in products such as Ick Guard II® by Jungle, and Formalite III® by Aquatronics (which also contains copper). While it is non-staining and said to be safe for live plants (and at lower dosages…) scaleless fish, eggs and fry, it is nevertheless a strong chemical – a preservative for biological specimens (AKA embalming fluid). It may damage your biological filter, deplete oxygen levels in the aquarium, and destroy invertebrates and weak fish. Its toxicity increases with water temperature and acidity, making it a questionable choice for soft water fish.
Malachite Green is an ominous substance that’s highly effective against Ich and fungi. It can be purchased separately under its chemical name, or found as the active ingredient in products such as Maracide® by Mardel, Ich Cure® by Aquatrol, Super Ich Plus® by Aquatronics, and Fungus Plus® by Aquatronics. It is carcinogenic and dangerous to handle or breathe (especially for pregnant women). There are rumors circulating that it could be banned for aquarium use by the FDA in the future. It cannot be used on food fish and is toxic to eggs, fry, some varieties of tetras, catfish, elephant noses, loaches and small marine fish. It also may damage your biological filter and will likely stain aquarium decorations and silicone sealant. Malachite Green is light sensitive, and you will be advised to keep your aquarium lights off during treatment to prevent the chemical from oxidizing.
Formalin and Malachite Green are often used in conjunction with one another. The two chemicals are said to have a synergistic effect when combined, having a greater impact together than either one by itself. Products include Rid-Ich+® by Kordon, Quick Cure® by Aquarium Products, Cure-Ick® by Aquarium Products,Ick Guard® by Jungle, and Formalite I® by Aquatronics. This combination of chemicals is probably the most common choice for treating ich.
Acriflavine is a chemical found in some Ich medications such asIck Clear® by Jungle, and Acriflavin Plus® by Aquatronics. It is considered to be highly effective against protozoan parasites, as well as external bacterial infections and fungus which sometimes occur as a secondary condition. It may damage your biological filter, harm live plants, cause skin irritation, and stain your hands and tank decorations; gloves are recommended. I do not know how well it is tolerated by invertebrates, sensitive species, scaleless fish and fry, but I do know that it cannot be used on food fish – which is sometimes a clue as to the toxicity of the substance. As always, read warning labels thoroughly.
Methylene Blue is used primarily for superficial fungal or bacterial infections, and nitrite or cyanide poisoning. It is also considered to be an alternative to Malachite Green for the treatment of fungus and external protozoa in sensitive fish, eggs and fry. It is available under its chemical name or in products such as Methyblu® by Aquatronics. It too cannot be used on food fish, and is a powerful dye that may stain tank decorations and silicone sealant. Damage to plants and biological filter may also occur.
There are other antiparasitic medications available, but I believe I’ve covered those most commonly used. Clout® by Aquarium Products is one more worth mentioning since it appears on nearly every LFS and pet store shelf that carries fish and is often recommended as a cure-all. It is an extremely strong blend of medications which I am unfamiliar with, including dimethylamino, phenylbenzylidene and cyclohexadien. I believe it is best suited for internal parasites. It is definitely not to be used with scaleless fish. Read the label carefully.
There are a few products that have been developed which take a completely different approach to treating Ich than those outlined above. One is Stop Parasites® by Chem-Marin. It utilizes a proprietary blend of food-based ingredients including hot peppers, which may be safer for you and your fish than traditional meds. According to its creator, the product took eight years to develop. It apparently stimulates the fish’s slime coat production to excess, which causes the parasites to slough off, or be shed. Then it provides a “false host” for the parasites to feed upon which is more desirable than the fish. Kent Marine makes a similar product for saltwater parasites called RxP®. I cannot endorse either product, never having used them, but if you are open to homeopathic-type treatments and want to experiment with something other than salt or raised temperature, this product might be for you.
A Final Word:
Most strains of Ich will respond to the treatments described here. However, researchers have recorded rare instances where trophonts were able to encyst and reproduce without leaving the body of the host fish, essentially skipping the second life stage described above. Obviously this is a menacing thought, but one to be considered should all attempts to eradicate the parasite fail. In such an event, it would be impossible to destroy all the organisms and the frustrated hobbyist would fight an endless battle with repeated outbreaks of the disease. Euthanasia would be the only humane option. Let me stress, however, that I read about this in a research paper and have never heard of this actually occurring to a fellow aquarist. Let’s hope it never does. □