Koi Pond Regular Weekly Maintenance
Water Changes
The most important thing you should do with your pond, is to remove atlease 15% of the water in the pond every week and replace it with new fresh water. Doing this solves many problems, and dramatically increases your water quality, and let your koi's immune system keep them healthy. Real koi kichi (koi nuts) change 15% of the water every day.
Evaporation is a big issue here in Arizona. As water evaporates, it leaves behind minerals in the water, so if you only "top off" the water, what happens is the minerals build up and screw up the water quality. Keep in mind that koi came from rivers, which are continually supplied with fresh rain water.
Another side benefit is that koi produce a natural hormone that prevents the growth of koi. This is a natural defense mechanism so incase a bunch of koi are stuck in a small pond in the wild, they don't outgrow their habitat. So regular water changes will help dissapate that hormone, and speed up growth.
Tips For Water Changing
For draining the water, most people have ponds in the ground and often will use their main filter pump to partially drain their pond water. The problem is it takes a long time, gets boring waiting for the water to drain, and sometimes gets forgotten and whoops... come back and the whole pond is drained.
I discovered a technique that works pretty well. Setup a special pump on an electrical timer that is used only for changing water. This pump is not fully submerged, it is only deep enough in the pond that if the pump is accidentally stuck on, it will only drain down to the 15% level. Better to let the pump run dry, than to kill all your fish. And most pumps have a thermal cutoff, so if you do let it run too long it will overheat and shut off itself, and then be able to run again after it has cooled off.
For filling your pond, it takes forever with a garden hose and if you forget and leave it running & change too much water, you will shock your fish and kill them. For instance, my 3000 gallon tank takes about 50 minutes to refill the 15% regular water change. I have tried just about every mechanical crank timer on the market and they all fail after a while, usually they stick in the on position.
The solution I use is I setup a regular lawn irrigation timer and solenoid valve (sprinkler system timer). I don't use the auto timer part, just the manual run for X number of minutes feature. The picture to the right is my setup, because I have a bunch of quarantine tanks, I made a pvc T tree and a hand valve / hose that runs to each tank.
Filling Your Pond - Use A Sprinkler Head
Tap water has clorine in it, and koi naturally investigate waterfalls (and streams of water) so if you fill your pond with a hose, the koi will swim right up to the hose and start breathing water that has a concentration of chlorine in it. This may burn their gills and cause damage. To fix this problem, setup a sprayer or sprinkler head on the end of your hose so it sprays the water around your pond as it fills it. Not only does the spraying aerate the water to help dissapate the chlorine, but it also dilutes it quickly with pond water so the resulting concentration that the koi breathe is very low in chlorine.
PH and Baking Soda / Oyster Shell (chicken grit)
An ideal PH for koi ponds is around 7.6 to 8.2. Ponds built from concrete and with a large amount of rocks in the system tend to keep their PH balanced just fine. Ponds which have a plastic liner and all plastic parts tend to have problems keeping their PH at an acceptable level. If your pond PH drops below 7.6, then you should add baking soda to increase the PH. Add 1 cup per thousand gallons, per day until the PH is back up to the proper level. A better, longer lasting solution is to add some crushed oyster shell which will slowly dissolve and buffer your water, so it will keep a stable PH. Crushed oyster shell is commonly sold as "chicken grit" at local feed stores, about $10 for 50 lbs. Just put some chicken grit in a net bag, and put it in your pond near water that is flowing.
Filter Flushing & Cleaning
You should flush your filter atleast once per week. The good bacteria in filters aerobic, and the newer colonies perform the nitrate conversion process at a much faster rate than old colonies of bacteria, so by flushing the filter you get rid of the anaerobic muck, and also sluff off the old colonies of bacteria, so new ones can form. I have a home made barrel filter that I installed a knife valve in, so for me it is as simple as turn off the pump, open the valve and stir with a stick. Whatever filter you have, configure it so that it is easy to do, so you will do it more often.
Full pond clean out - WARNINING - you can kill all of your fish!
Good filter designs collect water and debris from the bottom of the pond so you never build up a muck layer. However many ponds I have seen in people's back yards are not configured that way, and they have layers of muck, leaves and debris. That muck layer builds up over time, and then occasionally owners do a big "clean out". This is very dangerous and can kill all of your fish in just a few minutes.
What is happening is that that muck layer creates an anaerobic environment which harbors toxic bacteria and substances. If you disturb this area while the fish are in the pond, it will release those toxins in the water and kill the fish. So if you want to perform a big "clean out", you should remove all the fish to a temporary holding tank and then perform your clean. After the clean out, get the pond running again for atleast 3 days, and then you can start to replace your fish a few at a time.
My pond water is clear, doesn't that mean it is healty water?
No. Clarity has nothing to do with the quality of the water. Ammonia, nitrite, and nitrate are all toxic to koi. You can have perfectly clear water, and kill your fish, or significantly stunt their growth. To see what levels you have, you need to test your water with test kits. If your filter is operating properly, you should have almost no ammonia and no nitrite. The nitrate is the least toxic to koi, and it will build up in a pond. The only way to get rid of nitrate is water changes or a signifiant supply of plants. But just becuase you have plans, that doesn't mean you can skip the water changes - you need to do those regardless of plant load.
Feeding
Koi can be pigs and consume mass amounts of food, and on the other hand they can survive on small amounts of food. The more you feed, the bigger they will grow, but keep in mind that you need a filter that is big enough to handle the amount of food you feed. Koi can survive and be healthy on as little as 0.5% feed rate, per day. On the other hand, owners looking to get maximum growth are known to feed up to 3% feed rate per day. If you feed less than 0.5%, then the koi start to become stressed, and start having health issues.
The way to calculate your feed rate (the amount of food you feed), simply calculating the body weight of the koi you have, and figuring the dry weight of the food you feed. So if you have 29 lbs of koi (464 ounces of koi), then a 1% feed rate is 4.64 ounces of koi pellets per day.
Koi and goldfish to not have somachs, they just have a long intestine. This means it is better for them to graze on food all day long instead of just one big feeding per day. So you should split the food and do multiple feeds per day. A common feeding schedule is to give them some food first thing in the morning when you wake up, then some right after you get home from work, and the rest right before you goto bed. If you can split it into 5 feedings per day, they can process the food much better - and this helps them grow faster.
NOTE: If you find uneaten food in your pond, then something is wrong. Either you are feeding too much, or you have water quality problems, or your filter isn't big enough, or something else. Also see below about the temperature to stop feeding.
How To Calculate The Weight Of Your Fish
The simplest method I have found is to make estimations based on the length of the fish. What you do is place something in your pond that you know the length of, such as a decoration or even just a stick. As the fish swim past the item, you can see how long they are compared to that item. You can even take photos as they go past, so you can look at the pictures to help with the comparisons.
You then make a list of all the fish you have, and how long they are. Now that you have their lengths, you can use the following average lengths to figure how much they weigh. This may seem complicated or laborsom, but you really only need to do it once or twice a year.
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(the length includes tail fin) |
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4" 0.62 oz 5" 1.21 oz 6" 2.09 oz 7" 3.33 oz 8" 4.96 oz 9" 7.07 oz 10" 9 oz 11" 12 oz 12" 16 oz |
13" 20 oz 14" 26 oz 15" 30 oz 16" 40 oz 17" 45 oz 18" 56 oz 19" 66 oz 20" 77 oz 21" 82 oz |
22" 102 oz 23" 120 oz 24" 134 oz 25" 150 oz 26" 160 oz 27" 180 oz 28" 210 oz 29" 230 oz 30" 150 oz |
How To Calculate The Dry Weight Of Your Food
First you need to figure what container and scoop works best for you. I personally use a peanut butter jar and it's lid as the measuring cup, however many people use a big plastic jar and a real kitchen type measuring scoop. Whatever measuring scoop you use, put 10 scoops of food into a container and measure it with a postal scale. Then take that weight and divide by 10, and you have a pretty accurate weight of one scoop your food. Write that on the scoop, so you know how many scoops your fish need. For an example, I found that my peanut butter jar lid holds 1.75 oz of my pellet food.
Homemade Koi Food
I have seen large healthy koi that were fed regular koi pellets PLUS large amounts of table scraps. I have become convinced that feeding your koi fresh foods is essential, because processed & dried foods seem to destroy the nutritional value of the ingredients. There are lots of recipies on the internet of how to make your own koi food.
For the food I make, I take koi pellets and run them thru my blender dry, this makes a powder. I set that aside, then blend up a bunch of vegetables to make what looks like a milkshake. I then mix that by hand with the powder, plus wheat germ, wheat flour, corn meal, and other random stuff to thicken it up. I split that up into portions that are the right size for 1 week of feeding. Then I move one portion to the refrigerator, and pull off chunks daily to feed to my koi. Not very scientific, but my fish like it. Also I feed cooked shrimp, and cooked tilapia.
When it comes down to it, Koi are basically river carp, and river carp are garbage eaters that scavenge anything they can. So I figure the more variety I feed my koi, the more of a natural diet they are getting.
Cold Water - Winter Break - No Feeding
A koi's metabolism is mostly based on the temperature. At temperatures between 60 and 87, you should feed the full daily amount. At temps between 56 and 60, you should cut the feed rate down to 0.75% or less. After the water temp drops to 52 and below (and stays down there), you should stop feeding until the temp rises back above 52 and stays there or above.
The koi go into a slow state and mostly sit on the bottom of the pond during this cold time, and they don't process the food very well. This is a normal part of their yearly cycle, they build up a lot of fat in the fall to carry them through the winter. Your filter will mostly die off also, so in the spring when you start to feed again, feed lightly for a while to build the bacteria up again.
Hot temperatures -- reduce feeding
One of the problems we have in Arizona is the water temperature can rise very high, I have seen temps as high as 96 in my tanks. One summer, the water stayed at 96 for about a month and a half. The koi reduce the amount they eat when the temp gets above 88, so if you notice this, then cut back on the amount you feed.
Koi Pond Design Suggestions
If you wander around in online koi forums and get advice from online experts, they all seem to talk in exact terms and there are many common myths they push, and warn if you don't follow them, you are doomed.
One thing I have learned from rescuing koi from so many different ponds, is there is no single perfect pond. Infact, there are many, many different ways to have a koi pond and many different types of systems do work, and the proof is that the koi were living there for years and doing just fine.
Below are some of my suggestions and my personal observations, but these are not absolute terms -- they are simply my suggestions.
Why Koi Need a Lot Of Filtration
About five thousand years ago, Goldfish decended from Crucian Carp who which naturally lived in ponds. We know their age, because they appeared in Chinese artwork that was dated. The chinese kept them as a food fish, and the gold ones started appearing. Being a novelty, the Chinese kept the gold ones, and since they could make large ceramic bowls, they started keeping the fancy gold ones in their homes. The goldfish would spawn in the bowls, the ones that could take the poor water conditions survived, and today we have a very hardy fish which can live in horrible conditions. Since keeping goldfish was so easy, they are known as "the people's fish".
Common river carp first appeared in Persia and have been traded across the world as a food fish, and they are the most prevalent fish in the world. The carp have been intentionally introduced into public waterways as a food source, not only in ancient times, but also in the early years of forming the United States, our goverment launched a program to populate our public waterways with carp just as many other countries have done before.
The Koi we know are genetic mutations of river carp. Koi are incapable of producing some of the pigments that river carp do, and so instead of having a nice camoflauge color, they have fancy patterns. Koi have been selectively bread for about 1000 years to enhance the color patterns and also modify various body shapes, such as trying to get the mouth to point more forward, and have specific shapes to the thickness of their body parts like trying to smooth out the big hump in their back.
Because Koi decended from the common river carp, which evolved in a river environment - they have biological systems that prefer lots of fresh water like you will find in rivers. So the filters we use need to be able to clean the water a lot better than what you would use with goldfish or other types of fish.
Pond Size
You need a minimum of 1000 gallons for the first koi, then 300 gallons for each additional. This might seem like a lot of water when you look at a little 12" koi, but you have to keep in mind that the koi is going to continue growing and it will be very big in just a couple of years. Serious koi enthusiasts have 1000 gallons of water per fish. Many somewhat-serious koi enthusiasts have ponds in the 3000 to 5000 gallon size range, and the super serious have swimming pools that are converted into ponds in the 15k - 30k gallon size range.
That being said, the vast majority of rescues I have done are from 500 gallon ponds, and the koi had been living there just fine for many years. The reason for rescue was mostly because of the house being sold, new babies in the family, or other koi non-health related reasons.
Pond Depth
The two main predators that attack koi are Herons and Raccoons. They both hunt in similar ways, they wander into the pond in the shallow end, and then wait for a fish to come close, and then strike. One of the best defenses against this is to have a pond with walls that go straight down for 24" or more. As for overall depth, koi like deep water, like in the 6' to 8' range. This is not practical for most casual pond owners, so please consider atleast 24" or greater depth. Many typical ponds I see are 3 to 4 feet deep.
Pond Shape
Because Koi decended from river carp, they love to have a constant current to swim in. A perfectly round pond (a cylinder) is very easy to get a current running, and is the ideal shape for koi. I have round tanks I keep my koi in, and just to keep it interesting, I'll reverse the flow about once every couple months so it goes in the opposite direction. Most pond owners prefer to have other shapes, so do what you can to make a current they can swim in.
How a Biofilter Works
A pond filter works very differently than a pool filter does.
What is going on is that koi eat food, then:
- They produce waste which is organic matter plus ammonia.
- There is a type of bacteria that eats ammonia, and converts it into Nitrite.
- There is another type of bacteria that eats nitrite, and converts it into Nitrate.
- Algae & plants eat the nitrate.
- And finally the koi eat the algae and plants, starting the cycle over again.
The bacteria described above grows on the surface of everything in your pond, the only problem being that the pond walls and pipes in your pond are not big enough to have enough area, to grow the amount of bacteria to process your waste products. So chambers full of "media" is put inline with the circulating pump, and the bacteria grows on the media.
The media could be lava rocks, pea gravel, bio balls, pvc shavings, pot scrubbers, bubble beads, or whatever - the point is to make a large surface area for the bacteria to grow on. As the water is pumped thru the media, the bacteria can feed on the waste products and do their conversions.
Sizing your Filter
As you can see from above, the size of filter you need is based on the amount of waste your fish produce, not the water volume. In the pond articles secion, I have specific numbers for calculating the amounts of various media you will need to handle specific feed loads. A good general rule of thumb is that you need 10 gallons of media for each 24" long koi. If you have 5 of 24" koi, then you need 50 gallons of media. Some media is more effecient than others, so you might need more of one and less of another.
Pump & Flow Rate
The minimum actual flow rate you should be atleast half the pond volume, per hour. So if you have a 1000 gallon pond, the actual flow rate of your pump should be atleast 500 gallons per hour. It is much better to have a flow rate which will turn your pond over 3 times per hour. The higher flow rate will help aerate the pond better and make your biofilter run more effeciently.
Note that I say actual flow rate. The rating of your pump is how much water it can push at the exit port of the pump with no load. As soon as you push water through a pipe or above the water level, the load goes up and that reduces the flow rate.
Testing your actual flow rate is easy, just get your filter running and put a 5 gallon bucket under the discharge and time it. Typically pumps will run with at an actual flow rate of half the speed indicated when using the various standard filters I see people using.
Algae
There are many types of algae, and it is GOOD for your pond - the koi eat algae, and it helps the biofiltration. The problem is with the free floating "pea green soup" algae, it blocks your view of the fish which you spent all this time and effort to have. The best way I have found to get rid of the green soup algae is to setup a UV sterilizer with it's own pump.
A UV sterilizer is basically a light bulb inside a tube, and as you push the water past the light bulb, the UV light rays kill everything. Each UV sterilizer has a manufacturer's rating of how fast you should run the water through it, so you will want to get a seperate pump that matches that flow rate.
After you use the UV to kill the free floating algae, the algae on the walls will have a better chance at growing and will take over the job of consuming nitrate. Your koi will eat the algae off the walls, and not only is it good eating, but algae has compounds that enhance the red colors in koi.
Typically you will want about 9 watts for around 700 gallons. The bigger the UV the better. The bulbs only last for about a year though, so you will need to get a new bulb each year.