How do you avoid Fungus on Fish Body

[Dajuyu]

Just bouncing back this question, I know the water quality is indeed the de-facto for fish health.
But what other steps to be taken to completely completely avoid fungus issue on fish body ....

 

[Essjay]

Anything which stresses a fish will lower its immune system making it more susceptible to disease. Water quality is one stress factor. Other stress factors include -
Tank size - a tank that's too small causes stress
Numbers of shoaling fish - too few of shoaling species is stressful to them
Water chemistry - a fish which must have very hard water will be stressed in very soft water for example
Incompatible tank mates - if one fish feels threatened by another it will be stressed
Decor - do fish which need hiding places have anywhere to hide
Fish numbers - an overcrowded tank is stressful to a lot of fish

 

[Colin_T]

Fungus or excess mucous?
A lot of people think their fish have fungus when in fact, it is excess mucous.

There are numerous types of fungus, however the most commonly seen on fish is Saprolegnia. It looks like white fluff sticking out of the body. This type of fungus can only infect fish through damaged/ injured tissue. If the fish does not have any injuries or open wounds, it won't get a Saprolegnia fungal infection.

There are other types of fungus that can infect fish but they are not common, nor easy to see or identify without taking samples from the fish. Many of these fungi can infect healthy tissue and live almost in harmony with the fish.

Big water changes and gravel cleaning the substrate on a regular basis can help reduce the number of disease organisms in the water and this can help reduce the chance of fish getting all types of infections including fungal infections. Cleaning the filter regularly will also go a long way to reducing diseases and infections in fish.

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EXCESS MUCOUS
Excess mucous is commonly seen on fish that are stressed out from poor water quality, chemicals in the water, incorrect water chemistry for the species, aggression from other tank mates, and diseases.

Excess mucous appears as a cream, white or grey film or patch/es on the fish's body and or fins.

If fish show any signs of excess mucous, the best thing to do is check the water quality for ammonia, nitrite, nitrate and pH, and then do a huge water change and gravel clean the substrate.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

If the water quality is good and the fish continue to show signs of cream, white or grey patches on their body or fins, they might have an external protozoan infection like Costia, Chilodonella or Trichodina. These can be treated with salt (sodium chloride) at a dose rate of 2 heaped tablespoons of salt per 20 litres of water. Keep the salt in the tank for 2 weeks.

 

[Slaphppy7]

Anything which stresses a fish will lower its immune system making it more susceptible to disease. Water quality is one stress factor. Other stress factors include -
Tank size - a tank that's too small causes stress
Numbers of shoaling fish - too few of shoaling species is stressful to them
Water chemistry - a fish which must have very hard water will be stressed in very soft water for example
Incompatible tank mates - if one fish feels threatened by another it will be stressed
Decor - do fish which need hiding places have anywhere to hide
Fish numbers - an overcrowded tank is stressful to a lot of fish

I would add temperature to that list, as well...too high or too low for a given fish can be quite stressful

 

[Avel1896]

You can avoid 90 even 95% of diseases : maintenance/hygiene above any suspicion AND no stress by respecting fishes lifestyle and requirements coz stress leads to diseases even the most serious ones.