Adrian R Tappin

First Published: ANGFA Bulletin: Issue 14, December 1992

An article describing his experience with the treatment of white spot and velvet disease in Australian native fishes.

Two years ago I was maintaining 46 aquariums in my fish room ranging in size from 55 to 550 litres. Due to my personal situation at the time I found that I was unable to give them the commitment that they deserved. I made a very hard decision to reduce this number and consequently, today, I only maintain 28. I decided it would be best to get rid of the smaller aquariums and now the smallest size that I maintain is 105 litres, 190 litres being the average.

This reasonable sized reduction in aquariums also meant a reduction in the number of species or varieties that I could maintain. The reduction in the number of aquariums was the easy part, choosing what species that I would keep created some heartache. This was eased somewhat with the cooperation of Rod Campbell, a fellow ANGFA member. We have decided to share our species with each other and in doing so we take turns at breeding certain species. We then pass onto each other, 6 or 8 specimens of the particular species that either one of us is breeding. This way we do not have to breed every variety we are maintaining.

You may wonder what all this has to do with fish disease. Well, when I decide to breed a particular species I usually raise 40 to 60 young fish to adulthood so as to pick the best 10 or 12 for my future population base. The problems come about when I have to find room in my diminished number of aquariums.

This ultimately leads to overcrowded conditions particularly when the young are almost fully grown, while they are small the problem is not so bad. I usually raise the young adults in a 190 litre aquarium. This of course requires good aquarium management practice to maintain optimum water quality. However, regardless of the effort that you put into aquarium maintenance, problems do arise.

The most common disease problems that I encounter are white spot - Ichthyophthirius multifiliis and velvet disease - Oodinium sp.. In crowded conditions these two diseases can become epidemic and create considerable loss. The answer to this problem is to have an effective treatment that you know will work quickly. I would like to share with readers my solutions for these conditions.

As anyone who has visited an aquarium store knows, there is no shortage of commercial medications available for treating fish disease. Fish medications sold and used in the aquarium hobby vary in quality and effectiveness. In fact, some fish medications do not work. There is nothing to prevent a manufacturer from claiming that their product cures any disease they wish to list on their labels. The use of inappropriate medication also wastes valuable time.

The hobbyist must also be aware of the use of some substances, for example, Methylene Blue often sold as a fungicide and parasiticide, will inhibit or destroy the denitrifying bacteria in aquarium filters, with the probability of fish fatalities due to toxic ammonia or nitrite levels.

It is advisable to use only those fish medications that list the active ingredients on the label so that you know what you are using. Some manufacturer's recommended dose level is often less than the scientifically recognised therapeutic dose. However, it is not a safe practice to simply change a manufacturer's recommendation.

The following is my choice of medicants:


Quick Cure, manufactured by Aquarium Products USA and imported by Aquarium Products, 15 Antoine Street Rydalmere NSW.

The active ingredients as per label are a tri-chelated formula of: Formaldehyde - 1031.0 g/litre and Malachite Green - 19.2 g/litre. The recommended dose rate is 1 ml per 76 litres of aquarium water.

Unfortunately, I have found this rate to be ineffective and I use 1 ml per 40 litres of aquarium water. I do a 50% water change using a gravel syphon cleaner and as most of my aquaria have undergravel filters I remove the airstones from the lift-tubes and place them into the aquarium proper. This prevents the medicant from being drawn into the gravel while at the same time providing aeration. Usually only one treatment is required. However, if you find that the fish are still affected, miss one day then do another 50% water change and treat again. No more than three treatments should be used.

I have found that Rainbowfish, Blue-eyes and Gudgeons will tolerate this concentration. Care should be taken with scaleless fish and other sensitive exotic species as malachite green at the above dose levels may be toxic to them.


My choice of medicant here is Oodonex, a product manufactured by Aquasonic Ply. Ltd., Ingleburn NSW and is sold for the treatment of Oodinium and Cryptocaryon in marine aquariums.

The active ingredient is Copper Sulphate 14.13 g/litre. Dose rate is 1 ml per 9 litres each day for 4 days. That dose rate is for saltwater, NOT FRESHWATER. The reader is cautioned to proceed with extreme care if they elect to use copper sulphate as described. My dose rate is 1 ml per 10 litres of aquarium water and only ONE DOSE. Again I do a 50% water change before treatment.

My aquarium water is hard and alkaline. If you have soft water a little experimentation may be required. The toxic effect of copper sulphate is increased in soft water. I would use half the dose and keep a close watch on the aquarium inhabitants during the next 12 hours. If the fish show any signs of distress do an immediate water change.

I have had fish completely covered in velvet and within 24 hours after the one dose, the velvet has completely disappeared. If however, the fish still show signs of the disease after 24 hours, miss a day, do a 50% water change and give a half dose, e.g. 1 ml per 20 litres of aquarium water.

Again, I repeat that any hobbyist using my dose rate to do so with extreme caution. Copper Sulphate treatment can be unpredictable under certain aquarium conditions and is extremely dangerous to some species of fish, plants, catfish and snails. It is also important to keep in mind that all fish medications are toxic to fish. Fortunately, it usually takes a higher concentration of the drug to harm the fish than it does to harm the pathogens. Nevertheless, subtoxic doses for the fish are still stressing, and repeated doses can build up to toxic levels.