If you've ever been in the presence of a pond full of koi fish for an extended period of time, you may have noticed that under certain circumstances, these acrobatic fish can (and will) actually jump out of their habitat. There are many factors that may cause a koi fish to potentially give themselves a death sentence, as fish are typically unable to survive outside of water for very long.
Importantly, however, are the lifesaving and mitigation measures that any koi fish owner must be aware of and be able and willing to initiate when and if this situation arises in order to maintain the health and well-being of this exquisite member of the carp family. Healthy fish equals happy fish! Sick fish could lead, unfortunately, to dead fish.
Jumping koi fish would most certainly be a sight to see if they end up landing back in the water, but alas, they are not known for their intelligence. However, they would surprise the average person with their "athletic" prowess by jumping a lot higher than one would expect.
Koi fish have the ability to jump as high as 6 feet out of the pond water, but it usually ends up being just a few feet above the water surface. Enough to put their very lives in peril!
The two primary reasons that would cause a koi to want to escape their life in the pond for greener pastures, so to speak, are poor water quality and lack of oxygen or levels that are insufficient. Maintaining a healthy pond for koi fish requires routine testing of the water every couple of days for chemical imbalances, nitrate levels, proper water temperature, water level and water that is clear of debris that could impede fish movement.
A proper pump and filtration system will ensure the movement of clean water throughout the pond and keep the oxygen at a vital level. While koi fish sometimes will swim to other preferable areas of the pond where the oxygen level may be better, they will gasp for air at the top of the water or potentially jump out of the pond altogether to seek oxygen elsewhere if their environment proves to be deficient.
Koi carp are curious fish. Not a bad trait to have, but one that can get them in trouble from time to time. This inquisitiveness can lead them right out of the water if they see something that peaks their interest enough for them to try and get a closer look.
A word of caution needs to be noted here to never reward a jumping koi fish with excess food as they will most surely associate jumping with the welcome reward of something good to eat.
Overcrowding in a koi pond can be another cause for the fish to try and escape, especially during mating season when the males become more aggressive. It can also be a cause of oxygen depletion, waste build up and added stress which directly correlates to the possibility of a viral or bacterial infection, especially if the koi becomes injured.
Natural behavior will lead to breeding which, in turn, increases the number of koi fish fighting for available food resources so it is crucial to limit the amount of fish depending on the size of the body of water.
Since jumping from their outdoor pond is not typical normal behavior, it is inherently essential to determine the underlying cause in order to prevent permanent damage to this beautiful fish population. While the root cause may not be obvious at first, several different solutions can be initiated simultaneously which would hopefully prevent any further behavior patterns that would ultimately be detrimental to the physical health and safety of the koi fish.
Make sure the pH balance of the water is at a safe and sustainable level - The nitrate level should preferably be between 7.0 and 7.5, but could comfortably go as high as 8.2 in order to prevent bacterial infections. Most often, the level of ammonia in the water can be at very dangerous levels.
Invest in a top notch filtration system so clean water can circulate around the pond reducing harmful bacteria and low levels of oxygenated water.
Reduce Overcrowding to prevent aggression and disease among the fish which would potentially cause them to try and escape by jumping out of the pond.
Increase the height of the sides around the pond - Fish that make smaller jumps would most likely be contained within the pond if they aren't able to clear the area surrounding it. Outside predators, such as cats or raccoons, would also be unable to reach inside the pond to injure or kill the koi fish.
Add Netting - While this may not be an option that many people would want to consider because it would detract from the ambiance of their fish pond or aquarium, a covering over the water would be a sure way to contain the koi within the pond and prevent unwanted jumping. Netting would also have the added benefit of keeping predators away.
All animals, including fish, have patterns of behavior that may be interesting to observe. Some behaviors can be awe inspiring when we are lucky enough to catch a glimpse, such as a dolphin jumping out of the water and landing safely back in the ocean or an orca breaking the surface for a moment of air.
Sometimes, however, animals can provide indicators that something is not right by some of the behaviors that they exhibit which may be out of the ordinary, such as a whale stranded on a beach or an indoor cat that hides in a dark closet for an extended period of time. Koi fish are no different; if you catch them jumping out of their habitat then that may be a clear signal that their well-being could be at stake, even if the reason is strictly due to their curiosity, because they are ill equipped to survive outside of water for any extended period of time.
If essential life sustaining necessities for the koi fish are available within the pond - clean and healthy oxygenated water, proper ammonia levels, sufficient food supply, lack of a threatening predator or external temptation (i.e. food rewards outside the pond) - then there is a much greater chance of maintaining an environment full of healthy and happy koi fish!