Water chemistry and how it effects your Koi

09 Apr Water chemistry and how it effects your Koi

The Core Elements of Poor Water Quality and How They Affect Pond Fish

There are several  core elements that contribute to poor water quality issues, each one with its own characteristics and potentially dangerous effect on pond fish. Each individual element requires its own testing kit and should be monitored to ensure their presence in the pond water is within acceptable parameters.

Poor quality pond water is responsible for a large majority of the disease, sickness and health problems pond fish experience. However, to fully understand the subject of quality pond water, you need to understand how certain individual elements affect the health of pond fish.

Core Elements of Poor Water Chemistry

• pH
• Nitrite
• Ammonia
• Water Hardness
• Chlorine

Having a better understanding of each individual element allows us to learn how fish behave and respond when negatively affected.

Nitrite – Ideal Value in Pond = Zero

Nitrite transforms haemoglobin to methaemoglobin, which has no capacity to act as an oxygen carrier. This means Nitrite is very toxic to pond fish, as they need haemoglobin to carry out its oxygen carrying functions within their blood. Therefore, as nitrite levels rise in the pond water, oxygen capacity in the blood of the pond fish dramatically reduce. This results in a lack of oxygen for the fish and leaves them gasping for oxygen at the pond surface.

pH – Ideal Value in Pond = 7.0 – 8.0

Koi can withstand some variance in pH levels outside of their preferred range of 7.0-8.0, but long term exposure to pH levels outside of acceptable parameters can cause serious health issues. pH levels under 6.0 cause severe erosion of sensitive areas on the pond fish such as the gills. This creates high levels of irritation and discomfort for the fish, ultimately leading to severe infections. This condition is called acidosis and is very dangerous for Koi. If pH levels elevate over 9.0, it can create a condition called Alkalosis, which is a form of metal toxicity and very harmful to Koi. Koi fish with Acidosis or Alkalosis, become very active and excited, even thrashing around at the pond surface.

GH and KH – Ideal Values in Pond = GH of Above 10° dH, KH of Above 6° dH

The level of particular dissolved minerals determines water hardness. General hardness (GH) is a total of particular dissolved minerals in the water and represents the total water hardness.

Carbonate hardness (KH) is a measurement that represents the contribution of the minerals to alkalinity. The KH is the most important factor for Koi, as it determines how much resistance a pond has against a crash in pH levels.

Koi fish add to acidification of pond water because they release carbon dioxide, much like we do. The carbon dioxide ultimately turns into carbonic acid when it dissolves in the water, which puts downward pressure on pH levels.

There are some dissolved minerals which can absorb acids, which counteracts the downward pressure on pH by the acids. The minerals are responsible for the alkalinity of a pond and are primarily carbonates, bicarbonates and hydroxides.

Chlorine – Ideal Value in Pond = zero

Chlorine is very toxic to pond fish and causes severe erosion of gill tissue, eventually causing pond fish to stop breathing and die. Tap water is full of chemicals that are dangerous to fish and must go through a thorough purification process before being used.

Poor quality pond water can make pond fish behave as if they are infected with bacteria such as gasping for air at the surface of the pond. However, their behavior may be a result of low oxygen levels in the water, which can be caused by low pH levels or ammonia and nitrite poisoning.

If your pond fish are behaving in a strange manner, it is extremely important to determine the quality of your pond water before attempting to apply a treatment of any kind. Water quality must always be corrected before any treatments are added to the pond.

Because of the issues mentioned above, water quality is very important to managing a pond of healthy fish. Frequent water tests and water changes, along with staying on a strict maintenance schedule will help you maintain quality pond water for your Koi.