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!
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.
hallwill6 years ago
OK First off Kudos!! The pond is awesome!!!.. Now what about teh overall view? Have you finished teh rest of your landscaping project? Also what would you do different if you could do it all over?
koncept (author)  hallwill6 years ago
Thanks! We did finish the landscaping and it has made the distance from the house to the road seem so much bigger, even with the wall. I added some overall view pictures so it would be easier to visualize the finished project. They are under Step 15. We still plan to add a small fence on top with gates at the wall openings for a little more privacy and give it a "cottage feel". As far as what I would do differently; nothing with the design. But I would probably move the hole for the electrical wires lower and closer to the wall. You can see it in some of the steps. We generally hide it with plants. My original idea was to have a water fall built up in the back corner. We may do that one day, but I am no positive it would fit with the front yard. We love the pond though. My fiance even made seat cushions for the smaller curved wall (idea for another instructable ha!) The only other problem area so far is getting the pot out for winter. The filter tube is in there really tight so it makes it sort of difficult to remove and reinsert. If you use something that can withstand winter it wouldn't be a problem (for example, rocks instead of a ceramic pot).
Idea might be to use those quick disconnects for hoses. Like th eones that they have on the portable pressure washers... Just a thought.. Thank you for the reply and updates...
KEUrban6 years ago
Beautiful work and an outstanding instructable. Congrats on being named a finalist!
King Crab6 years ago
Wow, this is a really nice instructable! Great job!
rredmon6 years ago
I honestly was skeptical when I read the title with the word ultimate in it. but this is far beyond anything that I would have thought it was. Great Job, Good Idea and Good structible.
koncept (author)  rredmon6 years ago
many thanks
eash6 years ago
Wow. This is absolutely amazing. Thank you so much for sharing this. Congratulations on making such a beautiful pond. I have to be careful not to let my turtle know about it, because then she'll be wanting her own pond!
alston6 years ago
this truly is an excellent Instructable. kudos!
koncept (author)  alston6 years ago
Thanks so much, let me know if anyone has questions!
whopoder6 years ago
Really, really, beautiful! Thank you for share this Instructable project.
Coati6 years ago
That is beautiful,I love fish ponds and just about everything to do with the water.This is certainly one of the nicer designs I have seen.Plus being so close to tho road the concrete walls give you your own guard rail.
peguiono6 years ago
I like it a lot :] just an idea for you to ponder but I think you should add a grate or something over the overflow just in case in a rain storm or something you don't loose any fish.
koncept (author)  peguiono6 years ago
thanks, yeah during a heavy rain the water of the pond becomes level with the overflow hole and just dribbles out like a skimmer on a pool. But my fiance did joke about that too. So far so good. Thanks for the idea!
Do you find that the koi when they get larger they smash up and eat the plants? Which then blocks up the pump and filter? its an ongoing nightmare with us, the filter has to be completely cleaned at least twice a week and we only have three koi, but a few goldfish as well.
koncept (author)  TehLonelyOne6 years ago
Our largest fish are only about 12" so far but they don't seem to mess with the plants too much. In the warmer months we do clean the filter about every week or so. I know they are eating machines.
Punkguyta6 years ago
That is sooo F-in cool man!! 1+ for sure
glfr_grl156 years ago
This is cool. How many fish do you have? How many do you think it will hold safely?
koncept (author)  glfr_grl156 years ago
thanks, we started with 5 and then they bred and now we have like 25... do you want any fish? ha we are talking about building another in the back yard so we can move all the babies! But it should be large enough for the amount we have and maybe a few more :)
lshdesign6 years ago
This is great! I love the idea of the low wall to sit at. Has a cottage feel to it. Looks like it is plenty big for a lot of fish. How deep is it? Does it keep it from freezing over winter?
koncept (author)  lshdesign6 years ago
thanks, it does freeze over but is far deep enought for the fish to live. It is just shy of four feet deep. It also has 18-24" depth under ground (below the frost line) during years of a bad freeze.
rivetgeek6 years ago
Thats a great looking pond, you might want to invest in a uv biofilter though as is keeps the fish healthier and the water crystal clear.
koncept (author)  rivetgeek6 years ago
I will take a look, i know there are tons of types of filtration systems. Our pond has stayed very clear and i do various tests for water quality. Thanks
Meggeler6 years ago
Beautiful. Excellent concept especially when landscaping a new house. Mine (pond) looks like an after thought - oh, it is! :)
sageserver6 years ago
how much money was it to make? I always wanted to make one. is it high maintenance?
koncept (author)  sageserver6 years ago
Well the whole yard, all the walls, pavers, plants etc. was a few thousand, but if you just built the pond it maybe around 1000 bucks. As for maintenance it is very easy. I recommend cleaning it out once a year in fall, other than that you just feed the fish.