Cotton Wool Disease

What causes Cotton Wool?

Cotton Wool is a general name for fungal infections that are present in aquariums and feeds upon dead organic matter. Healthy fish protect themselves from fungal infections by producing mucous layers. When this is disrupted, fish can become infected with fungus.

Cotton Wool can be caused by:

  • Any previous infections, parasites or injuries(Ich, Finrot, Ulcers)
  • Rough handling and physical injury can damage the slime coat
  • Water quality changes that also include temperature increase. Outdoor goldfish ponds can suffer from sudden rise of temperature (in Spring)
  • Organic matter, uneaten food can increase the likelihood of an infection

What are the symptoms?

A cotton wool like growth of fine, white strands is the most obvious symptom. There can also be grey or brown wool patches on the goldfish's body, fins and mouth.

Click image to enlarge.

How to cure Cotton Wool?

Treatment can be relatively easy if done with antifungal agents or salt baths. Treating the sick fish in a separate hospital tank is preferable. One tablespoon per gallon of water can be used when doing salt baths.

Very common treatments include Malachite Green, Jungle fungus Eliminator(US) or Anti-Fungus-Remedy(UK).

How to prevent Cotton Wool?

Maintain a high quality water, doing regular water changes, remove uneaten food or any dead material. Keep a close watch for any wounds or infection.

While you should not need a doctorate of nursing practice degree to be able to see any signs of wounds or infection, make sure you know what you are looking for. Following these suggestions for nursing your goldfish back to health should do the trick.

Rule of thumb: clean, healthy and well oxygenated water combined with a constant water temperature keeps your fish far away from diseases or problems.

Do not use extra medicine or combine these treatments one after another!

Love to you,

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