I have copied some of this from an article by a chap called Graeme Robson I read it on another forum I am sure he will not mind me sharing his advice and incites as he has drawn these methods and knowledge from lots of other Loach keepers. I have used his advice once, fortunately I have only had one incident of Ich in over two years and it worked.
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.
I have spoken with a lot of aquarists that keep Loaches and especially Clown Loach and they 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 harbour 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 and other Fish in your tank 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, adding an air stone will only add a very limited increase of oxygen saturation to your water. 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 to be a very effective treatment for Ich.
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 bio filtration cycle and a comfortable home for your fish.
This is obviousley just one way of removing Ich from a tank its up to you if you choose it or another method, but when you remove the Ich from your fish and the tank you then have other issues to deal with other members have already eluded to and that is size of tank and fellow species numbers.
Eventually Clown loach can become very large and bulky fish requiring tanks 6 foot in length and sometimes bigger. As juveniles they can be kept in 4 or 5 ft tanks, but you will have to take into account the number of Clown loach you have? as well as filtration and flow in your tank but one Clown loach on its own is really not fare even if it came from another tank with other species of fish that it is familiar with they are not its own kind so are completely insufficient .
Like all fish species Clown loach require specific conditions and I recommend you do some study there are plenty of people who can help you out when you have done with your immediate problem that is if you decide to keep Clown Loach.
Good luck regards onebto