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Fish health and water quality

water quality home page

"Look after the water and the fish will look after themselves." That just about sums up just how important water quality is to fish health. Indeed, unless conditions are right, fish health problems, disease and fish losses will follow as sure as night follows day.

The birth of water

How water is formed: oh, and by the way, you don't think that rainwater is pure - do you?

Fish are open systems

and are thus affected by changes in the surrounding water. Understanding this is fundamental to all aspects of fish health

The unusual character of water

It's strange stuff, but without it there would be no life on Earth and no fish in ponds!

Osmosis and osmoregulation

 are major factors in fish health and easily affected by water quality, stress, and disease.

The final cocktail we call pure water

It is an amazing cocktail that has a major influence on fish health.

Fish are like leaky parcels

of water swimming around in a tank or pond - no wonder water quality is so important to fish health.

Defining water quality

With over 90% of all health problems related to poor conditions do you meet the 5-point standard?


The silent killer always ready to strike


Not quite as dangerous as ammonia, but still a major threat to fish health.


What is it? an important topic that affects virtually every aspect of fish health and water quality.

Water hardness

A major water quality factor that affects fish health, water quality and disease treatments- yet few fish keepers check it!



Has a major influence on all aspects of aquatic health as well as  oxygen levels and fish immune systems.

Water testing

The key to fish health. What and when to test


is very useful to control elevated ammonia levels - but it must be used correctly!



Fishdoc would like to thank the following benefactors for their sponsorship of this site: - Sho Koi - Aquadyne Bead Filtration - - Koizyme (Genesyz Aeromonas Fighter

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