KOI HEALTH INFORMATION
Nitrogen Cycle
The Nitrogen-Cycle in a koi pond?
The koi pond nitrogen cycle is the process of breaking down fish waste, toxins, and other debris in your ponds by good bacteria. It is a natural process which occurs in a well-balanced ecosystem like ponds and lakes. The nitrogen cycle is responsible for the biological filtration within the system.
The waste products of the fish, plants, along with other dead organisms and any uneaten food, are broken down by bacteria into ammonia. In the nitrogen cycle, ammonia is broken down by an oxygen-loving bacterium, (aerobic bacteria) called Nitrosomonas. The Nitrosomonas bacteria feed on both oxygen and ammonia, and then they excrete a byproduct called nitrite. Another aerobic bacterium, Nitrobacter also utilizes oxygen and in a similar way, it essentially changes the nitrites into nitrates. This nitrate is then used as food source for pond plants and algae. And so the process begins all over again.
It is very important to understand and to control the levels of the nitrogen cycle in your pond. Every koi keeper should own a simple test kit to monitor the water quality of their pond water and note the levels for referral. Chemicals such as ammonia, nitrite, nitrate and others are not apparent visually. Perfectly clean clear pond water can contain dangerous, even lethal levels of toxic chemicals. So if you think your pond is perfect as the "clarity" is good, just remember, the toxic substances in the nitrogen cycle are not visible, and your fish could be suffering without you knowing anything about it.
Ammonia
Koi and the effects of ammonia
Ammonia comes from many sources and is very toxic to fish in the aquatic environment. Fish naturally excrete Ammonia. Ammonia is released from fish’s gill tissue when it breathes. It is also released from the fish’s vent when it urinates and defecates. Additionally, decaying organic debris and uneaten fish food create ammonia, this will accumulate in some areas of a pond. Ammonia is extremely toxic, even at low levels to all of the pond inhabitants.
Ammonia can exist in two forms when dissolved in water, the first is the free ammonia and this is very poisonous to fish. The second form is known as ionized ammonia which is not quite as harmful. Ammonia can have a number of detrimental effects on pond fish such as reddening of the fish’s skin and disrupting the ability to regulate water and salts. It will also damage delicate gill tissue, causing swelling of the tissue which may hinder the absorption of oxygen.
If your koi pond water becomes polluted with ammonia, partial water changes need to be performed immediately to reduce the concentration of the pollutant. This may need to be done at varying levels depending on the amount of ammonia found, but water changes of 20-30% every day for a week is not uncommon.
What is a safe Ammonia level for a koi pond?
The ideal ammonia level for your koi pond is 0.00 ppm, (parts per million), but as this is almost impossible to reach, you should aim ideally for a level of less than 0.2 ppm. We always try and employ a warning system to alert at different levels.
Green 0.2 or below - all is well, Amber approx 0.3, warning, need to start to thinking about some course of action, Red 0.4 and above, ACT NOW!!
Anything over 0.3, your fish will be greatly affected by the ammonia levels. The fish’s gill filaments cannot function normally; they cannot excrete the ammonia that is accumulating within its body. The ammonia will build up internally resulting in fish death.
What are the symptoms of high Ammonia in koi ponds?
Koi that are suffering in high levels of ammonia will become irritated and will exhibit symptoms such as burns on fins and gills, clamped fins, isolation, or lying on the pond bottom. You may notice that your koi are secreting excessive slime or mucus, experiencing reddening of the fins and skin, and may be gasping at the pond surface. The consequence of prolonged exposure to elevated ammonia will be damage to fishes slime coat and skin, gill malfunction and damage to the delicate gill tissues; resulting in the ideal condition for bacteria to attack the gill tissues and a perfect environment for parasites to flourish.
How do you remove Ammonia from a koi pond?
Ammonia that is accumulating in your koi pond must be reduced in order to maintain good fish health. With the introduction of beneficial bacteria you can reduce the risk of ammonia damage to your fish. Partial water changes are very helpful in reducing high ammonia levels in koi ponds, although pay close attention to the temperature of water being added. In addition, it is suggested that feedings are stopped or at least be reduced massively to help combat high levels of ammonia.
Nitrite
Understanding Nitrites in your pond
Nitrites are not considered as harmful to your pond as ammonia but even at low concentrations in the pond, it can be stressful to your koi. High nitrite can cause irreversible damage to your fish’s liver, spleen, nervous system and kidney damage. Nitrite poisoning may even result in the death of your fish. This is known as brown blood disease.
Ammonia is converted into nitrites by good bacteria called Nitrosomonas. Nitrites are converted to nitrates by Nitrobacter.
When Nitrobacteria breakdown nitrites in the pond environment nitrates are produced. Nitrates are a natural by-product of the bacterial reduction or removal of ammonia and nitrites in the koi pond ecosystem.
What are the symptoms of high nitrite in the koi pond?
You may notice fish gasping at the pond surface or hanging near air stones if nitrite becomes problematic. High nitrite concentrations can result in a condition known as ‘brown-blood disease’. Brown-blood disease occurs in fish when their pond water contains high nitrite levels. Nitrite enters the fish’s bloodstream through the gills and preventing the red blood cells from absorbing vital oxygen from the water. It turns the fish’s blood to a chocolate-brown color. Hemoglobin, which transports oxygen in the blood, combines with nitrite to form methemoglobin, which is incapable of oxygen transport. Brown blood cannot carry sufficient amounts of oxygen through the fishes system; therefore the affected fish can suffocate regardless of adequate oxygen concentration in the pond water. This accounts for the gasping behavior often observed in fish with brown blood disease, even when oxygen levels are relatively high.
What is a safe nitrite level for koi?
The ideal range for nitrite is 0.00 parts per million, but again as per ammonia on a constantly fed pond, this is hard to reach. A reading of 0.25 ppm or higher is dangerous to your fish and indicates that you need to take immediate action to reduce the nitrite level in your koi pond.
As with ammonia, every koi keeper should keep their own test kit and perform weekly checks to ensure all is well. We recommend using the electronic handheld testers by Hanna Instruments, as they are far more precise using numbers not colours to identify levels in your pond.
What are the symptoms of high nitrate in my koi pond?
Accumulation of nitrates can cause problems such as damage to the veins in koi fins and skin, depressed immune system, and even reproductive problems. Koi in high nitrate conditions may act dull or lethargic but perk up and become energetic for a feeding then quickly return to the prior state of lethargy. Often, fish that are subjected to high nitrate accumulations over time will experience slowed growth, delayed wound healing and will become extremely susceptible to illness and parasitic infestations. You could also see multiple koi "flashing" and rubbing themselves on the bottom and sides of the pond, plus also jumping up out of the water surface with an attempt at removing the irritation to their skin.
What is the best way to reduce high nitrite levels in a koi pond?
If you encounter a situation where the ammonia, nitrites are rising to toxic or lethal levels you should do an immediate water change of at least 20-30%, for consecutive days until the levels have reduced. The newly added fresh water will not resolve problems associated with high or toxic chemical pollutants, it only dilutes them to a level acceptable to your fish.
Adding a good source of biological bacteria to your bio system is also advised.
Nitrate
What is a safe nitrate level for koi
The ideal range for nitrate is 20-60 ppm. If your pond reaches 80 ppm you should start some partial water changes to reduce nitrates to a safe level. Nitrate becomes extremely toxic above 120 ppm.
Pond pH
Understanding pH in a koi pond
The pH is a measurement of hydrogen ions as acidity and hydroxyl ions as alkalinity in the pond water; pH 0 - 6.99 is acid; pH 7.0 is regarded as neutral, and pH 7.01 - 14.0 is alkaline. pH (potential of hydrogen) is basically a measurement of how acidic, alkaline, or neutral your water is. It is measured on a scale of 0-14. A neutral pH of 7 simply means that there are an equal number of hydrogen ions as hydroxyl ions. A pH of 8 means your water is alkaline compared to neutral
The pH level can have a profound effect on the toxicity of ammonia. Alkaline water, with a pH of over 7.01 in combination with increasing temperature causes more of the ammonia to exist in the free form, which is very poisonous to Koi. If the water is alkaline it will affect the toxicity of ammonia and could be quite serious for the health of your pond fish.
It is also very important to understand that each single digit increase or decrease above or below neutral is ten times more alkaline or acidic than the neutral reading of 7. Any sudden change in pH of one digit or more is a drastic chemical change and could have devastating effects on your fish.
If the water becomes too acid or alkaline, and swings in one direction or the other, the fish have a means of adding acids or bases to their blood to counteract the changes and equalize their internal pH to that of the water. However, they cannot do this very quickly, and they cannot easily counteract a change in the pH of the water of more than three tenths. If the water becomes too acid or too alkaline too quickly, the fish are in danger of getting conditions such as Acidosis or Alkalosis. Both of these conditions can be fatal. An ideal maximum shift in 24hrs is no more than 0.3
What is the ideal pH for Koi?
Koi do best in a pH between 7.0 and 8.6 and are in trouble at a level below 6.0. A relatively stable pH of pond water is vital. Fish need to maintain a very similar pH level in their blood to stay healthy. For Koi to be healthy, they need a pH in the range of 7.0-8.6, and more importantly they need the pH to remain stable somewhere within in that range.
What are the impacts of high pH on koi?
Pond water conditions with pH of 8.5 or higher may result in a condition within the fish called Alkalosis. Symptoms include excess slime production, isolation, gasping at the pond surface, blood streaked fins, resting on the bottom, and finally death. Alkalosis is hard to reverse once the symptoms begin.
What are the impacts of low pH on koi?
Low pH levels create a condition called Acidosis in pond fish. The symptoms of Acidosis are similar to those of Alkalosis; a lack of appetite, production of excess slime, isolation and resting on the pond bottom and finally blood streaked fins and death. However, Acidosis is rapidly corrected when the pH level is raised to a suitable range.
How do I check the pH of my koi pond?
The proper way to check pH, is to take two readings with a suitable pH test kit. One should be taken in the early morning and the other should be taken in the late evening on the same day. In doing so, you should not have more than a 0.3 (three tenths) difference between the two readings.
How do I raise the pH of my koi pond?
If your pond experiences a pH crash, meaning the pH dives below 6.5 you can use baking soda at a rate of 1kg per 5000litres of water. Bicarbonate of soda has a natural adjustment to 8.3, so can be used to increase or reduce your pH.
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