Understanding Aeromonas and Psudomonas Bacteria in Koi Ponds
Pathogenic bacteria cause bacterial infections. Pseudomonas and Aeromonas bacteria are the most common types of pathogenic bacterium in the koi pond environment. Numerous strains of these bacteria exist, and they vary greatly in their ability to cause disease in koi. The most frequently type identified in koi ponds is Aeromonas hydrophilla. The bacteria exist in nearly every koi pond around the world. It’s inevitable; if you have a pond, you have Pseudomonas bacteria and Aeromonas bacteria living in it.
The Aeromonas or Pseudomonas bacteria enter the koi’s body through open sores on the fish or wounds caused by parasite bites and damage. They also gain access through the intestines; by fish eating tissue that is already contaminated with the offensive bacteria. Once inside the fish, the bacterium is carried through the bloodstream to every organ and cell. With the onset of stressors the harmful bacteria is allowed to flourish causing a myriad of disease. Aeromonas and Pseudomonas cause ulcers (also known as “hole in the side disease”) fin rot, mouth rot, tail rot, and bloat or Dropsy. If left untreated the damage inflicted will escalate and eventually kill the fish.
Since Aeromonas and Psudomonas bacteria already exist in our koi ponds it is fortunate that our koi fish have a natural defense mechanism that helps to protect them. The fish’s defense is their protective slime coat and their immune system. Aeromonas and Psudomonas bacteria are present in the pond environment and it is possible for koi to be exposed to and live with these pathogenic bacteria and yet remain healthy and uninfected. Problems arise when fish experience an increase of environmental stress factors, particularly those associated with poor water quality; high ammonia and nitrite levels, pH fluctuations, and low dissolved oxygen levels. These factors coupled with overcrowding, high organic loads in the water and heavy parasite activity will weaken the koi and allow the opportunistic pathogens to invade, encouraging the development of ulcers. The bacteria are capable of producing disease in weakened populations of fish, or in fish suffering from other stressors and disease.
Koi ulcers and body sores can appear on your koi fish anytime during the year. But they are often discovered in the spring, when parasites have been taking advantage of your fish's weakened immune system throughout the winter months. The fish’s immune system starts to diminish in cool water temperatures, but the Aeromonas and Psudomonas bacteria are still growing rapidly between 42° F and 62° F. The cold temperatures of winter and the fluctuating temperatures in the spring have a significant effect on the koi’s immune system and its ability to naturally fight off the offending bacteria. In water temperature of 60° F your fish’s immune system is operating at around half of its normal capacity. Unfortunately, pathogenic bacteria are not as affected by swings in temperature and will continue their assault on your koi during this time.
The overall health of your koi plays a significant role in the level of pathogenic bacteria it can be exposed to and not get sick. Diet is very important to the health of your fish. Offer your fish a high quality diet enriched with vitamins and minerals. Fish that are adequately fed will be better able to fend off the invasive bacteria.
The Aeromonas or Pseudomonas bacteria enter the koi’s body through open sores on the fish or wounds caused by parasite bites and damage. They also gain access through the intestines; by fish eating tissue that is already contaminated with the offensive bacteria. Once inside the fish, the bacterium is carried through the bloodstream to every organ and cell. With the onset of stressors the harmful bacteria is allowed to flourish causing a myriad of disease. Aeromonas and Pseudomonas cause ulcers (also known as “hole in the side disease”) fin rot, mouth rot, tail rot, and bloat or Dropsy. If left untreated the damage inflicted will escalate and eventually kill the fish.
Since Aeromonas and Psudomonas bacteria already exist in our koi ponds it is fortunate that our koi fish have a natural defense mechanism that helps to protect them. The fish’s defense is their protective slime coat and their immune system. Aeromonas and Psudomonas bacteria are present in the pond environment and it is possible for koi to be exposed to and live with these pathogenic bacteria and yet remain healthy and uninfected. Problems arise when fish experience an increase of environmental stress factors, particularly those associated with poor water quality; high ammonia and nitrite levels, pH fluctuations, and low dissolved oxygen levels. These factors coupled with overcrowding, high organic loads in the water and heavy parasite activity will weaken the koi and allow the opportunistic pathogens to invade, encouraging the development of ulcers. The bacteria are capable of producing disease in weakened populations of fish, or in fish suffering from other stressors and disease.
Koi ulcers and body sores can appear on your koi fish anytime during the year. But they are often discovered in the spring, when parasites have been taking advantage of your fish's weakened immune system throughout the winter months. The fish’s immune system starts to diminish in cool water temperatures, but the Aeromonas and Psudomonas bacteria are still growing rapidly between 42° F and 62° F. The cold temperatures of winter and the fluctuating temperatures in the spring have a significant effect on the koi’s immune system and its ability to naturally fight off the offending bacteria. In water temperature of 60° F your fish’s immune system is operating at around half of its normal capacity. Unfortunately, pathogenic bacteria are not as affected by swings in temperature and will continue their assault on your koi during this time.
The overall health of your koi plays a significant role in the level of pathogenic bacteria it can be exposed to and not get sick. Diet is very important to the health of your fish. Offer your fish a high quality diet enriched with vitamins and minerals. Fish that are adequately fed will be better able to fend off the invasive bacteria.
How do I prevent koi ulcers?
Keeping your pond parasite free is critical to maintaining healthy fish and reducing the chance of ulcers from Aeromonas and Psudomonas bacteria. Parasites bore through the protective slime coat of the fish allowing any existing pathogenic bacteria to create an ulcer. Keep the pathogenic bacteria level as low as possible by using good mechanical filtration to remove fish waste and organic matter quickly and often. It is also vital to boost koi overall health which in turn strengthens their immune system. Feed a high quality vitamin enriched koi diet and do periodic water changes.