Goldfish Slime Coat Maintenance

Goldfish Slime Coat

A goldfish has a protective slime coat that covers its entire body, scales and skin. This protective slime coat is a secreted mucoprotein that contains enzymes and antibodies that help the goldfish fight against infection, disease, parasites, and fungal pathogens. Not only does the mucoprotein keep these infections from getting inside the the goldfish, it acts as a barrier to keep in essential electrolytes that are required for osmoregulation as well as other important body fluids. Whenever there are breaks or holes in a goldfish’s protective slime coat, electrolytes and body fluids will leach out into the surrounding water.
a common goldfish breed

Slime Coat Problems

  • A white slime coat can be caused in response to a fish trying to fight off an infection, a pH problem or irritation from a treatment . (not to be confused with a fluffy white coat; that is a fungus. See list of diseases for info.)
  • Black is usually caused by ammonia burns due to high ammonia levels in the water.

The number one cause for a weakened coat is stress. A stressed out fish won’t secrete a healthy layer of mucoprotein, leaving itself susceptible to infection, diseases and parasites. The causes of stress in a goldfish include a long list, many of which are caused by the owners actions.

Poor Water Quality
  • Warm water conditions promotes bacteria growth
  • Drastic and fast changes in water temperatures
  • Chlorine and chloramine in the water
  • High ammonia levels causing ammonia burns (blacking skin)
  • Low oxygen or high carbon dioxide
  • Low or dropping of pH levels
Introducing a New Goldfish
  • Acclimating a new fish improperly or too fast
  • New goldfish might pick on or be picked on by others
  • Not providing sufficient hiding places for a new tank mate
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Handling a Goldfish
  • Transporting or moving a fish is stressful on them
  • Using a dry fish net that scraps the slime coat off
  • Open wounds and scraps add to the stress of a goldfish
  • Touching or petting a goldfish removes the slime coat

Maintaining a Slime Coat

Avoid improper handling, don’t neglect your routine tank maintenance and provide a happy tank environment for your goldfish. There are several products on the market that will help maintain or cure the weakened protective slime coat of a goldfish. These include: a chlorine remover and slime coat replacer, pH buffers beneficial bacteria that can help cycle a tank that helps remove ammonia and wound healing solutions.

Other treatments include: Aqueous aloe vera gel 5-30% that promotes healing; sodium carboxymethyl cellulose and polyvinylprolidone that contains a mucoprotein slime replacing compound; ethylendediaminetetraacetic acid which is a chleating agent; diazolidinyl urea is a preservative.




A Must Have for All Goldfish Owners:
Dechlorinator with Slime Coat Care
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Reviewed By: Tim Winter

Tim Winter has a strong affection for pets and wildlife. His years of experience caring for various types of pets has led him to share his knowledge with others on the best practices in pet care. Tim holds a Bachelor of Science from the University of Oregon School of Journalism and Communications.

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