...do you meet the five point standard?
1. Low ammonia and nitrite
Fish are constantly polluting their own environment and producing ammonia. Both ammonia and nitrite are highly dangerous, causing stress and physical damage to sensitive tissues. A major, major requirement of any fish keeping system is no detectable levels of either. This particularly applies to new set-ups (new pond syndrome) and heavily stocked koi ponds. Biological filtration may be needed to maintain optimum levels.
2. Chemically clean water
The water should be chemically clean and free of chemicals such as pesticides, chlorine, heavy metals, organophosphates and chemicals used to treat fish diseases. The presence of any toxic chemicals, even at fairly low levels, may be harmful. OK, we do have to treat fish from time to time - the point is to realise that any chemical treatment will compromise water quality, and for the duration, conditions (from the fish’s perspective) will be less than optimal.
3. Water hardness, pH and temperature
Different species of fish have specific requirements for essential water parameters such as pH, water hardness, alkalinity and temperature. Conditions outside of what are fairly narrow limits are liable to create stress. Water that fails to meet these criteria cannot for obvious reasons be considered good water quality
4. Low levels of organic pollution
In addition to fish waste, the pond or tank is also being continuously polluted with uneaten food, algae and other detritus. As this organic matter decomposes it produces many organic and inorganic compounds. Biological filtration will take care of ammonia and nitrite, but there may be a build up of dissolved and particulate organic compounds. High levels of organics (POCs and DOCs) can create conditions that encourage disease, parasites and opportunistic bacteria. Water with high levels of organic matter cannot be considered good water quality.
5. Stability not fluctuation
Depending on the water chemistry, stocking levels and pond design, it is possible to have substantial fluctuations of pH, temperature and other parameters over a 24-hour period. Constant changes - even if they stay within the preferred range are liable to be extremely stressful, as the fish have to constantly adapt to changing conditions. An example might be pH that varies between, say 7 in the morning, rising to 9-10 in the evening on a hot sunny day. Apart from stressing the fish, it will have other implications for other water chemistry aspects such as ammonia and many common disease treatments. Water that constantly fluctuates in quality and conditions cannot be said to be good water qua