Dealing with Ich

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Graeme Robson
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Dealing with Ich

Post by Graeme Robson » Tue Jan 06, 2009 4:34 am

Ich, or White Spot, is a protozoan parasite that exists free floating in aquarium water. Because loaches have very tiny scales, they seem particularly susceptible to infection from Ich, although it can affect all aquarium fish. The first signs of an infection may be rapid breathing, redness around the gill area, or the appearance of tiny white spots on the skin of the fish that resembles white sugar. Infected loaches may make sudden repeated rubbing motions against rocks or gravel in the tank. Loach keepers call this behaviour "flashing."

It is possible to conquer Ich in the aquarium, and the following guidelines are culled from experienced keepers of loaches. The first thing to do is understand how the life cycle of Ich works. This information is central to the solution.

“Ich” is the convenient way to refer to the organism Ichthyophthirius (sometimes Ichthyopthirius) multifilis. This parasite has three stages to its life cycle: trophont, tomont, and theront. The white spots on an infected fish are visible during the trophont phase of the cycle. The spots are actually scarring that occurs as the parasite burrows into the outer layer of the fish's skin. Beneath each white spot, the Ich is forming a tiny cyst in which it multiplies by cellular division. At this stage of the infection, the Ich is impervious to medication.

When the cysts mature, they burst and release thousands of the tomont stage cells into the water. The tomonts develop a slimy coat immediately after emerging from the infected fish, which allows each one to adhere to aquarium décor, substrate and even the glass walls of the tank. Once the encapsulation is complete, the organism begins a second stage of reproduction by further cellular division.

Finally, the Ich is released from the capsules in its theront phase. These theronts swim out in search of new host fishes and begin the cycle again. It is only during this free-swimming phase of the life cycle that medication is effective. Theront cells are not visible in the water.

Chemical treatment:

Many different products are available to deal with Ich, but perhaps the most effective products are ones that contain the chemicals formalin and malachite green (sometimes called malachite blue or Victoria green). Both of these chemicals are highly toxic and in some areas, their sale is restricted. They are carcinogenic, so great care must be taken to wash any body part that is directly exposed to the medicine or treated water. Products such as Rid-Ich and Quick Cure are available in most aquarium shops, but if you're not sure which product to buy, consult a knowledgeable clerk.

Because these products are so toxic, many loach keepers recommend dosing an infected tank at 50% of the level indicated on the packaging. Many of these products recommend dosing at one drop per US gallon, so it may be prudent to dose at one drop per two US gallons.

The speed of transformation between stages of the Ich life cycle is affected by the temperature of the water. The organism goes through all three phases of its cycle more rapidly in warmer conditions, so we recommend that the temperature of a treated tank be gradually increased to around 86 F (30 C). This has to happen gradually to avoid further stress on the fish. Some sources have said that temperatures above 86 degrees Fahrenheit alone will kill off the parasite. However, many fish and aquarium plants cannot tolerate these elevated temperatures long enough to complete a full life cycle of the parasite and effectively eradicate it from the aquarium completely.

The aquarists and regulars at Loaches On Line recommend the following treatment for Ich:

1. Do a 50% water change and vacuum the substrate well. This will eliminate half of the Ich cells in the tank right away. Make sure you clean all water changing equipment thoroughly and allow it to dry completely before using it again. You don't want to spread Ich to another tank, or reintroduce it to the infected tank during or after treatment.

2. Remove any carbon from the filtration system. Carbon depletes the active chemicals in Ich medication from the water. Throw this carbon away as it may harbor more Ich cells.

3. Gradually increase the water temperature over a period of 24 hours to 86F (30C). This is about the maximum tolerable range for loaches, but you should make sure that any other tank inhabitants will be able to survive temperatures that high. Exceeding this maximum temperature for very long can further stress or even kill many fish. We recommend increasing the water temperature with great care. Also, consider the temperature requirements of any live plants during this process.

4. Dose the tank with Ich medication. DO NOT add salt despite the advice that is sometimes given. Generally speaking, loaches can't deal with salt and it ends up being a further stress on them.

5. Try to increase aeration by either lowering the water level to allow a splash from the return flow of your filtration, or adding an air stone. Gill function of infected fish is usually compromised by the Ich parasite and they will benefit from increased oxygen supply.

6. Be patient and resolved. Wait a minimum of two days before dosing the tank again. Some aquarists have had success waiting four days between treatments. Remember - you want to expose the maximum amount of theront cells to the medication for the longest possible time.

7. Perform another 50% water change and then dose the tank again. This cycle of large water changes followed by medication is repeated AT LEAST four times. Just because there are no more spots on the fish, you can't be sure that Ich is not still alive in the water in the invisible theront stage. Remember to wash thoroughly after coming in contact with treated water!

8. Once the full course of medication has taken place, lower the water temperature slowly, back to your usual temperature, and place fresh carbon in the filtration system. NOTE: It is essential to continue treatment for at least three days after the last visible sign of Ich is gone. Some water borne cells may still be alive in the tank.

Ich infestation, by itself, is extremely stressful for fish, but combined with toxic chemicals and high temperatures the fish are truly compromised. The Ich medication may also damage the biological filter of the tank, so rising levels of ammonia caused by mini-cycling of the biological filter may further endanger a loach's health. Some fish may die during this treatment period, but others may survive. It can be brutal to wait for the chemicals to knock the Ich out as your fish are clearly in distress, but this method has been found by many here to be the most effective treatment for Ich.

To avoid the worst-case scenario of a full-blown Ich infestation in your fish tanks and your loaches, SET UP A QUARANTINE TANK! A simple ten gallon, unfurnished tank will do. All new fish should be quarantined before they are added to the community tank. It's also much cheaper and easier to medicate a small tank for Ich - plus a whole range of other parasites and contaminates. Keep new fish in quarantine for a couple of weeks at least, some recommend as long as a month. By that time, if Ich is present in the water, it will have shown up on the fish.

Also, avoid putting tank water from even the most reputable fish shops into your home tank. Net your fish out of the bag and place them in the quarantine tank. Be sure to test the water’s pH and temperature. If they are dramatically different, place the fish and water into a clean fish bucket, and slowly add quarantine tank water over time to try to equalize the water parameters. Do not simply dump the fish and water into a tank as you risk adding all kinds of nasty parasites and diseases that are invisible into what should be a clean tank. You also risk compromising their immune systems further through pH or temperature shock by putting them into a tank with vastly different water parameters.

Loaches are often wild-caught, and may arrive with internal or external parasites that will harm your other fish. During their time in the quarantine tank, keep your eyes open for any signs of these problems. Observe the new fish in the q-tank daily. Are they eating? Gaining weight? Active? Or are they pale, lethargic, uninterested in food? Do you see whitish stringy feces, or worms protruding from the anus? If any of these signs become apparent, treat them for internal parasites before adding them into your main tank.

The treatment above has been tried and tested and will minimize stress on fish in most situations. Once the tank has been cleared of Ich, your attention should shift to water quality and rebuilding a healthy and mature biofiltration cycle and a comfortable home for your loaches.

Treating with UV sterilizing filters:

UV sterilizers may simplify Ich treatment and avoid unnecessary dangers. While UV is not likely to exterminate all of the parasite quickly alone, UV radiation removes most of the parasite from the water and the remaining parasite can be killed with lower doses of medications or weaker medications and without raising the temperature too high.

This is particularly important in the case of hillstream loaches which are less tolerant of high temperature as well as formalin-based medications. UV in combination with weak (1/3 and perhaps even less) dosing of malachite green and/or salt combination or quinine-based drugs is quite effective and is thought to be less traumatic to the fish than a high-temperature malachite green+formalin treatment, possibly resulting the the loss of fewer fish.

Note that UV sterializers can only be used in well-established tanks; any attempt to use a UV in a newly set up quarantine tank is likely to backfire badly by uncycling the tank. Even in established tanks one should carefully monitor the ammonia and nitrite levels when treating with medications that may impact the biofilter (malachite green is a such medication).

All ich treatments work faster at higher temparature and UV is no exception. It is therefore still worthwhile to raise the temperature to the upper limit of the "comfort zone" for your fish; 80F appears to be a good setting for hillstream species.


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