Discus Disease aka Discus Plague

Discus Plague

About 10 -15 years ago Discus Disease had infected many hatcheries and had put over half of all breeders out of business. Up to about 8 years ago, Discus disease was quite prevalent. Fortunately today, Discus Disease has mostly been bred out of all Discus and is very uncommon.

Discus disease was first identified in 1986 in northern Europe. This was about the same time as the Cherbonyl Nuclear accident and some experts believe that they are directly related. It soon spread to Asia and then to North America.

Putting two fish together that are perfectly healthy, but from different hatcheries, will sometimes trigger the disease. Hence, it can lay dormant in healthy fish.

This disease also affects Angelfish and some other South American cichlids. All Discus are susceptible, but Wild Discus seem to have some immunity. Also, Discus that are raised from fry by you, in your water, are usually immune. Also, once a fish has been infected and recovers, they are mostly immune thereafter (although there is a rare chance of a reoccurrence).

The main symptoms of Discus Disease are a darkening of the skin tone (some strains like White Diamonds do not show this indication), listlessness, clumping in groups in the corners of the aquarium, not eating and slowly wasting away. These symptoms are nearly identical to a bacterial skin infection with less excess milky mucous production being the main difference. Always treat as if they have both.

The total duration of the disease is usually 10 days but can last up to five weeks if there are secondary infections. In that time, they will either die or slowly recover.

No one knows for sure what causes Discus Disease. It can infect through water cross contamination and water vapor in the air. If one fish has it, chances are all fish in the same room or nearby rooms will catch it. It will stay dormant for months and can re-infect new fish that are introduced months later.

The only sure way to eradicate it is to kill all of your fish and sterilize every nook and cranny of your house using ammonia. The best guess is that it is a virus to which the Discus are extremely allergic. To date, no pathogen has been positively identified. There is no known medication which will have a significant impact on it.

The best treatment is to isolate any infected fish IMMEDIATELY and treat them for secondary infection such as bacterial skin infection. Doing daily 50% water changes does help reduce the time of the infection. UV Sterilization is by far and away the best line of defense and will drastically speed up the recovery time with far fewer losses. A tank that has heavy UV filtration with 1 micron heavy flow sediment filtration is nearly immune.

After utilizing this type of filtration for 6 years, not a single reoccurrence was experienced. These filters can be expensive, but worth it to the serious Discus lover.

About 30% of the fish which contract it will die and the remaining 70% will fully recover.