Picture of The Ultimate Koi Pond
This is a guide to constructing a koi pond for your garden or yard. I designed this pond and the layout of our front yard in order to visually connect the house to the street and protect our house from traffic. We (my fiance, future father-in-law, one friend and myself) completely transformed our small front yard with garden walls, walkways, new stoops and a wonderful koi pond.

Here, I am going to share how we built a custom concrete pond that will last forever, protect the fish through the harshest of winters, provide easy maintenance and beautify your home.

We expanded our living space outside and are able to enjoy the pond year round. The pond provides extra seating in the small courtyard, visual interest and soothing sounds of running water. While sitting on the ledge you are able to sit and look into the pond and entertain your guests.

This project took a few weeks to complete. As you can tell in the photos there were many other projects going on in the construction of our new yard. In order to complete this project, moderate construction skills and knowledge are required but by no means do you have to be an 'expert'. The most difficult aspect is having access to the concrete forms and knowing how to properly set them up.

This instructable can be taken and applied directly, or the ideas and methods can be used to influence a variation of this design/process of your own. Good luck and enjoy!
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buck22172 months ago

Great pond, those koi will get BIG

ToolboxGuy2 years ago
Forgot to say what a great instructable this was! Thanks for sharing!
Dr Qui3 years ago
Hi, for filter pump you say you use a 1500 gallon per minute pump, do you actually mean per hour? I am trying to work out the plausibility and numbers for a proposed pond. I would think at 1500 gallons per minute the fish would have to be permanently swimming away from the pump inlet.
1500GPM?! Yowch! That'd be one polished concrete pond!
lol. that is all i have to say

That is awesome! But don't the fish go out the over flow holes?
Impressive! Is the pot empty? You might consider adding some gnarly volcanic rock/other very porous nonreactive stones in it loosely (even just gravel). In addition to algae scrubbers, there's also beneficial bacteria that will aid in eating up excess ammonia. If it works as is then carry on, but might be something to think about :)
itsbadlands5 years ago
Doesn't the cinder blocks you used on the planters messup your ph and leech lime into the pond?
Koi like fairly alkaline water and can tolerate up to 9.0, so it might not be a problem. I used to put little concrete statues in my goldfish tank to keep the pH high.
ivan_s4 years ago
good sketch
jbestell5 years ago
Looks great im jealous but there seems to be too much direct sunlight which might attribute to the algae bloom.  How are the koi not eating the plants, will they eat anything they can fit in there mouth so big plants are ok???? Im leaning towards a nice breed of goldfish so i can have plants to help with balancing the pond, Water Hyacinth sounds like money it actually filters the water as well may want to check it out.

jfuredy5 years ago
That's an awesome project.  I wish I had the time and/or money to build landscaping features like that.

But I think you meant that you used a 1,500 gallon per HOUR water pump.  1,500 gal/min would typically require a 10" pipe.  I think a 1,500 gallon per minute pump would turn that 2,000 gallon pond into a whirlpool!
domino885 years ago
Very nice instructable!  I too dream of building a pond like you when I have a garden one day.  I have had numerous aquariums in the past and now have a small 50 gallon pond on my balcony with a few comet goldfish.  It's been running super well.
I think your fountian concept is great because it will oxygenate the water and it a very pleasing feature in the pond.  I like the high wall around the pond. it gives it character and prevents the fish from jumping out.  The overflow is a good idea, but I would put a netting accross it, because the fish do jump out.  Better safe than sorry. 
Where did you hide your filtration?  In my pond design considerations, aesthetically hiding a large filtration unit ranks high on the priority list.  The larger the filter, the less maintenace is required.  The filter also needs to be located in an easy to access/clean location.  The filtering options you select will litteraly determine how much time you will need to spend maintaining, so I'm very curious what you have selected for that.
In terms of water quality, I also monitor nitrates (N03), they are not as toxic as NH3 or NO2, but they do tend to accumulate to stressfull levels for the fish.  In addition, NO3 is a fertilizer and that is what leads to algae problems.  In the cycle of the fish poop, it satrts as toxic NH3 which gets processed in toxic N02 by one typeof bacteria, then the N02 gets processed to the less toxic N03 by a second type of bacteria. Both these type of bacteria require oxygenated water to operate.  The N03 accumulates at the end of the cycle and there are 3 (4) ways to deal with it:
1- plants use it as fertilizer, so put fast growing plants that have their roots in the water (can be in a pot).  when they grow, they absorb/export the N03.
2 - partial water change 10% every week or 2 to slow the accumulation of N03.  This would be more effective in maintaining water quality than 2 complete water changes/year.  When you do a complete waterchange,   you also eliminate all the useful bacteria that keeps you eco-cycle going.  It takes weeks/months to re-establish it.  This would be when the toxic NH3 and NO2 will spike until the tank is cycled and the bacteria equilibrium is re-established.
3- there is a 3rd type of bacteria that absobs the N03 and that just releases harmless N2 (nitrogen = 79% of what's in the air).  But the challenge is that this type of bacteria needs a low oxygen environment.  So a traditional filter with high oxygenated water flow does not work well.  In nature, this type of bacteria lives deeper in the substrate at the bottom of the pond where there is little oxygen.  You can recreate this in a pond or an aquarium by having a deep sand bed.
(4)- If all of the above is not done and there is a bit of sun, this is where the ugly algae bloom comes in to consume the N03.  It's nature's way of dealing with it to re-establish a healthy balance.

So in all my experience, I learned that there is no need to fight mother nature with chemicals.  Once I understood the eco-cycle that I was trying to replicate at home, I could make sure that all the parts of the cycle where fulfilled and then enjoyed very healthy, low maintenance aquariums/pond.

It would be great if after a year or two, you updated your instructables with what you would have done differently (if anything) with the hindsight of experience.

Again, great job, I am really impressed with the concrete work!!
neutron75 years ago
That is a serious project! i like the pot-waterfall thing, how come in some pictures it is green (which i like) and in other pictures it is plain terracotta? just a different pot?
Same pot. The older pictures show the new terracotta pot while it still has the clay color, the green is actually algae growing on the pot over time as explained in step 14: Build and install the fountain, second paragraph last couple of sentences...
static5 years ago
Looks great. The only question I have is how secure is  it from being a drowning hazard to small children? I understand that first they would have to be able to crawl over the pond wall, but kids can be pretty resourceful when the sound of moving water attracts them, and they learn that there are fish to watch, they'll be back for sure.
PEAJEAN5 years ago
 How do you keep both the raccoons and the great blue herons from turning your lovely fish into a buffet table?  Everyone I know in our central Ohio area has stories about how their numbers of expensive fish "disappeared"....some without a trace.....(heron) or with minced koi at the edge.(raccoon).  Just wondering.  Sounds like a beautiful project, but in our area....a futile effort.   
Looks great but how do you stop algae from growing in the Summer. I built a koi pond also but had to abandon it because it got bunged up with algae in the summer depite circulating water
as with any real estate location location location!  I find placing my ponds -I have 3 and a fountain; bird bathes galore throughout my garden where its mainly shaded and cool with just the morning sun helps a lot!  Full sun grows algae at warp speed and so does a pond stocked with too many fish, thus producing an abundance of poop to fertilize the algae.  The rule of thumb is 1 inch of goldfish per 5 - 10 gallons of water.  An adult or large koi require a minimum of 25 gallons to live in.  Goldies can grow quite large!

You can also use barley straw to lower or is it raise? can't recall off hand the water pH which provides a less attractive environment for the algae to grow in.

Snails and plants can help too. 
The main goal with any ecosystem is BALANCE - too much of anything creates imbalance and lots of extra work!

BTW the fish also consume the algae and it is the green feed that gives them their brilliant colour!  Fish enthusiasts often pay $100's more for fish grown in algae ponds so green its hard to see the fish!

Please plan ahead how the fish will be kept over the winter if you are in a northern climate.  Fish are just as intelligent as cats or dogs and some become quite attached to their people!  All that is required is to keep them from freezing - I use a 90 gallon tank out in the unheated garage with a styrofoam top, sides and an air filter or bubbler.  The fishes metabolism slows right down to semi hibernation states  so they only need be fed about every 10 days, water plants and lily bulbs will keep nicely in the tank too.
My ponds are 100, 80 and 50 gallons... made with the drop in pond liners.  Only a couple of koi in the big one then fancy Shebunkins and fantails in the smaller ponds.  I made a filter/fountain with a huge terracotta flower pot filled with layers of gravel of various sizes. which runs all summer.

I even have lovely ceramic pots the big ones that I sealed the hole in the bottom with silicone and grow a water lily in and stock with a couple of little gold fish!
My fountain has a couple of little guys too because I don't leave it running 24/7 and those darned mosquito's are real opportunists!

So you don't have to go Big to have a nice water feature in your garden - even a betta is happy in gallon of water or the white clouds and tetra's do fine over a summer too outside.
Hey, a lot of algae problems are exacerbated by exposure to sunlight. Try shading portions with plants, etc. depriving it of excessive light can prevetn algae blooms. There's also "natural" products available online and at pond stores called "pond zyme" or "algae zyme" or somehting of the like, essentially they are algae eating enzymes, but I have no personal experience with those. But many fish keepers will say a green pond is a healthy (yet unsightly) pond.
animes256 years ago
wow, I didnt know that I already have a pound in my house but, due to mosquitos I had to retire the water, hope that works
 Actually, fish will eliminate mosquitoes in a pond.
Or just toss in a couple of those 30 cent common/comet gold fish from local pet stores. Comets especially are popularly known as "poor mans koi" (30 cents, can see why) but will easily get as big and beautiful if not more so than koi. They are often in the feeder fish tanks at the pet store.
koncept (author)  animes256 years ago
Yeah, just put in a small pump and get the water moving. Good luck!
The Landon5 years ago
nice formal pond!
this is real construction, clean, solid, perfect in everyway.
Mikey D6 years ago
Great job! And as you requested... ...a question: Exactly what did you use as a concrete sealer that will not harm the fish? I have a similar concrete pond in my front yard and need to seal it. Thansk for the motivation! Mikey
Nastan6 years ago
hey today or maybe tomorrow i will get pics of my koi pond that ive been having for around 10 years everything was hand built too even the waterfall
3DogKnight6 years ago
Where do you get the "gasket" material to waterproof the seam between the footer/pond bottom and the side walls?
Something else that might be worth a look is pumping the water through a hydroponic garden. That is the ultimate bio filter, and will probably make for even less maintenance. Once you have a pond, adding a hydroponic garden to it is surprisingly simple and cheap. This site has a lot of info (Australian site, but the main problem with that is just the choice of fish, which you've got covered):
AubreeMarie6 years ago
Hey hey, great work! wanna come to my house and do the same? Just kidding! No I'm not,
Anyhow, about the Koi. You said they will breed like crazy, and yes, they will but they will also spend a lot of time eating the eggs and (ew) their own young, so if you want to keep them babies you can pull plants after spawn with all the sticky eggs on em and put them in a large tank and let them grow from there. There's plenty of info on teh interwebz about goldfish breeding.
Also, those 30 cent comets that they sell int he feeder fish department at gold fish stores will get as big and as beautiful as koi, only for a LOT cheaper and will also cross breed with the Koi (all types of gold fish are generally the same species) giving you fun different varieties!
Have fun! I know this started as a hardscape project but you may soon find yourself more the fish hobbyist (it's happened to soo many, myself included!)
Calorie6 years ago
Wow, this is beautiful. Clearly you have just a tad of experience... For beginning pond hobbyist, I would like to remind them of goldfish. They are very durable fish, and need less care than koi. Goldfish can often do without the expensive water treatments. And goldfish are really beautiful when viewed from above. That is the way both goldfish and koi were designed to be viewed. Neither looks great when you see them from eye level. Great job. Keep up the nice work.
buchd Calorie6 years ago
Huh, I'd never thought about that (regarding the viewing from above). Are there certain types of aquariums that are good for this if you have goldfish?
Calorie buchd6 years ago
You know, that's a good question. I'd always thought goldfish to be boring until I saw them in a pond. They were beautiful and very peaceful fish to watch. I never understood why they were bred in their forms until I saw them hovering in the water. As far as aquariums goe, I really don't know. There are some exotic ones with big bubbles under their eyes, and others with growths on their foreheads. There are tons of sites on the web. Read around and see what you find.
buchd Calorie6 years ago
Cool, thanks, I'll have to look into it. =)
animes256 years ago
how do you get the mosquitos to not reproduce in your pound?
There are types of native US fish that eat mosquitoes. They are called mosquito fish. I do believe that goldfish do the same thing.
koncept (author)  animes256 years ago
Mosquitoes need still/stagnate water to reproduce in. The fountain creates ripples in the water so mosquitoes would not lay their eggs/larva here. The water pump also is cycling the water which is not conducive to mosquitoes.
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