This disease is also known as Mouth Fungus and if your fish gets this disease, you must treat him immediately. This disease is extremely contagious and infectious. A fish with Cotton Mouth Disease will have a whitish fungus around the lips and cheeks. The lips will get swollen and rot away an a strip of rotten lip could stay attached and go in and out of the fish`s mouth as he breathes.
Symptoms of this disease also include a loss of appetite and they will become lethargic. If the fish is not treated, the fungus will attack the whole head and the fish will die. If a fish gets this disease, it would be advised to put him in another tank and treat him quickly because the other fish will catch this highly contagious disease and it is not worth losing all your fish over just one fish.
You can try to treat the infected fish by swabbing the mouth with a soft cloth saturated with a strong salt solution and then keep the fish in a bucket or bowl of strong salt water. You can also try swabbing the fish`s lips with a 5% silver mercury mixture.
If you want, you can make a solution of Terramycin or Aureomycin by dissolving 50 mg. per gallon of water. There should be a rapid recovery within 48 hours. One of the most popular and common ways of treating this disease is to use Methylene Blue solution. Your fish should be added to a tank that has the treatment in it and the Methylene Blue turns the water a deep blue color, hence the name.
Even though this disease is not nearly as common as White Spot Disease, it is extremely important to treat the fish as soon as you notice something doesn`t look right, because it can spread very quickly to other fish in the tank. For more info, you can visit: http://aquariums.aquariumspot.com
Image source en.wikipedia.org used with permission