Fungus Disease

The most common cause of death in goldfish is fungus disease. The fungus is usually in the water but the goldfish will only become effected if it's immune system is low, this can happen following an injury. The obvious signs are small fluffy spots or dots around the affected area.

If you have many fish in a tank and you notice this condition on maybe only one or two fish, they should be removed from the tank to stop other fish from contracting the fungus disease. You can place these fish in an isolation tank and buy a anti-fungal treatment from the pet store and treat them.

Another method to help infected fish is to place them in an isolated tank, add 3% of salt to the water and leave them in it for around 15 minutes. This translates to about 30g of salt to 1 litre of water. Be warned, do not use table salt for this as it contains iodine which can harm the fish.

While you do not have much control over whether your fish will contract a fungus disease, you can do you part by keeping the tank clean and ensuring there are no sharp objects in the tank that could damage your goldfish's scales.