Koi Health 101
Koi have lived with parasites and other pathogens since the time of their origin. Koi in a well maintained pond can live in a natural coexistence with parasites.
Remember, the goal is not to annihilate your Koi with every known medicine. A panic approach to disease control usually kills the parasites and the Koi.
When Koi scratch or act odd do not immediately dump chemicals in their home. Use the process of elimination we discuss below and treat for specific problems. Calm down and use common sense; give the Koi some time to recover from mild problems with improved water quality and filtration. Just like a dog or cat who has fleas we do not over kill the situation. Over kill can cause bigger problems down the line. Prevention is the key. Good water quality and fewer fish tend to be a more suitable approach to prevention. Take care of your water and filtration the water will take care of the Koi.
If we observe abnormal Koi behavior we must look into the possible cause. Abnormal behavior may be the result:
- Stress factor
- Specific disease organism.
The Koi's symptoms are a generic reaction. The symptoms are not a conclusive indication of disease. We must first understand and alleviate the cause of the stress before we can successfully treat any disease organisms. Let's consider the process of alleviation.
We can begin by testing the pond water and environment first.
- Test for oxygen. Results should be above 5 PPM, preferably 8ppm or higher.
- Test for ammonia and nitrite. These tests should read zero.
- Test the pH. A range between 7.0 and 8.8 is acceptable. However, daily fluctuations of more than 0.2 are stressful. A stable pH is important.
- Test for Nitrate. Concentrations from zero to 200 PPM are acceptable but should normally be below 100ppm.
Careful consideration should be given to your filter system and your pond maintenance.
- Check the pond for obvious dirt and organic matter. Dirty ponds consume too much oxygen and are a breeding ground for pathogens.
- Check for temperature changes. Have the Koi recently been exposed to temperature changes of more than 5°F? Thermally stressed Koi take time to recover their full strength and may fall prey to pathogens during recovery.
Check for chlorine.
- Chlorine and Chloramine are added by the city water companies to disinfect tap water. Untreated tap water will kill your Koi very quickly if not neutralized. Be sure to use a proper tap water conditioner on all new tap water going into the pond.
Do not allow any runoff from your garden to enter the pond.
- Fertilizers are extremely toxic and should be used cautiously around the pond.
Have new Koi been recently added?
- New Koi will be weak and may need time to adjust.
- New Koi can initiate disease outbreaks.
- New Koi can have parasites which may spread to the others.
- Adding new Koi may require preventive treatments or quarantine.
The Importance of Aeration
Pond aeration is one of the most important things you do for your pond! If you have ever asked the question of why exactly you have a pump pushing water over a waterfall, the answer is simply that it is keeping your fish alive. One can not have enough aeration. The Koi thrive better, bacteria in bio-filter are healthier! By increasing the "Oxygen" levels in the pond water, it will promote an overall healthier pond. One important area that higher levels of oxygen saturation help is in better promotion of good biological bacteria known as aerobic bacteria.
Aerobic bacteria are the good bacteria in our pond that like oxygen. They grow and eat dead decaying plants, algae and pond muck up to 30 times faster than anaerobic bacteria (an-aerobic). Anaerobic bacteria live and grow in the absence of oxygen. Maintaining a constant supply of oxygen greatly improves the ability for the aerobic bacteria to thrive and keep your pond cleaner, the water clearer and fish healthier.
It is a common belief that having pond plants will aid in providing oxygen to the fish. This is true, however, during the night, the plants use oxygen too. If you have too many plants, you’re taking away the oxygen the fish are using. Although a pond aerator will help with this problem, it is good to manage how many plants you have feeding off the water.
Ponds that are designed with bottom drains permit better oxygen disbursement towards the bottom because water usually enters the pond's top surface and is drawn out from the bottom drain. This method recirculates the pond's total water column better than those that do not draw the water from the bottom. More oxygen content close to the bottom promotes the good bacteria which consumes waste that settles on the bottom, oxygen is a great oxidizer in itself!
Decaying plants/debris/uneaten food in a very low oxygen level pond can create a toxic dissolved gas known as Hydrogen Sulfide. Hydrogen Sulfide (H2S) is a gas that can form in aquatic gardens and ponds, when certain bacteria feed on organic debris in areas of the pond that are low or depleted in oxygen. The most common way to detect H2S is by a rotten egg odor that may bubble out of the water when bottom sediment is stirred-up while seining fish, planting, or conducting general maintenance. H2S may be more prevalent in ponds and aquatic gardens that have been established for several years and have been heavily stocked with aquatic plants and animals. This is because organic debris accumulates on the bottom sediment surface, preventing oxygen to diffuse into the pond bottom.
Aquatic gardens require that you drain and clean them on a yearly bases for the reason of removing dead decaying debris trapped in rocks, nooks and cranny's. As there is no bottom drain and as a rule only a skimmer unit with pump. This allows debris to settle to bottom and not be caught in a flowing water column to be removed from system. One way to improve this is to add a Air Diffuser to pond or air stones placed in various locations. You will need a outside air pump to perform these steps. This will cause a water column to start drawing bottom water to surface for gas exchange.