I bought a few discuses and throw them into my main tank without quarantine. In any case, my main tank contains 3 adult discuses that I have neglected for quite a while now. These 3 adult discuses have survived pretty harsh condition so I thought they will be OK.

After a few days, I noticed some new discuses were not doing well. Tried water change but regardless of how many times I change, the water contains a lot of stringy material that collects at the top. Then some discuses appears to develop white patches that is visible when looking at the angle. First, I tried salt treatment and methylene blue. It doesn't work. Then I purchased protozin and followed the instruction. Nothing works. In desperation, I turn off the filter and repeat the protozin treatment.

Things get worse after the second day. I notice that one adult discus has white fungus all over the body and the tail of the second one has rot badly. This is when I read about Tea Tree Oil being used in Melafix. I do not have other medicine except protozin and methylene blue but I do have some pure tea tree oil that I bought at a supermarket in Australia. In desperation and before visiting the fish store, I put 2 drops of tea tree oil into a cup and fill it with water and then pour about 1/4 cup into the fish tank. The fish tank is 240 litres or about 50 gallon in size. I was worried about the effect of the tea tree oil while visiting the fish store to look for some medicine but was put at ease after finding the fish still swimming when I returned.

To my surprise, I notice that the white fungus on one discus has receded noticably and the fish were clearly getting better the next day. I changed water completely and then added 2 drops of tea tree oil. The next day, the fungus has receded further and barely noticeable. What's left is the scar but I am happy that the fish are recovering.The other one where the tail is rotting is also better. I also notice that the fungus on the lesser affected discus has disappeared completely as well. I repeat the treatment for seven days and happy to say that all the discuses are now happy and eating well.