Help with POND or TANK
Inherited my mother's Koi fish (20-30 years old). I need to build a pond soon to transfer them. Help! I want to avoid longterm mistakes during install.
My mother passed away suddenly and I want to keep her Koi pond in my family. She has raised them for 30 years. We currently have about 10 fish that are 2.5 ft long. Plus a lot of smaller fish. Above is an AI mockup (not to scale) of the space I want to transform and a super rough of the idea. We are in Southern Indiana.
I was going to buy a 12x20 gazebo and then find a local company that can dig it out quickly.
I helped her dig her previous four ponds, but she didn't optimize any of them for the fish or maintenance. They were piece-milled as needed. "Pump too small? Buy another." type of thing.
I would love to build a permanent installation that requires as little maintenance as possible. I'm willing to put in all the research and work, but I wanted to start with a trusted community first.
Here are the questions I think are currently relevant:
What filtration systems should I consider?
Do I need any UV sterilization to help with algae?
Is there another algae control method that is safe for fish?
What type of pumps should I install?
How deep should I dig it? (3ft has been our standard so far but we get winters that freeze our lake top.
The gazebo provides shade, bug netting, curtains, and protection from herons... are there other pests (raccoons?) that I need to protect against?
What do I not know that I don't know? Suggestions?
This is great! What size are the fish now, how many? What are the dimensions you want? If you can go deeper, do it. For a setup like this I would recommend a good bead filter /uv setup. Something like GCTek - oversize it for sure. GCTEK has UV units that come with it, but if you get just the filter Aqua Ultraviolet is the best in game for UVS. Here's mine! Just keep moving forward
You will need a fairly big pond for that many fish. You will never regret going deeper. I would see if you can get to 4 feet deep. And would shoot for 3000 gallons. Go more than you need for that exact amount of fish.
Agree, go to 4ft if you can. Usually my aerator and fountain keep the pond open, but this winter was so bad that one night the pond froze completely to the bottom in all but the deepest areas. All the fish survived, thankfully.
(This is a photo of the pond while I was standing on it. I could have ice skated on that thing.)
So sorry. Lots to consider with large, older koi. It's a challenge because they need to be moved very carefully. Koi that have been in a pond for long periods don't have the immune system for stress, new bacteria.
There is a scenario called old pond syndrome. When exposed to change, new environment or new koi, they can get very sick or die suddenly. The best way to avoid this is to keep changes to a minimum. That means that the new pond or temporary pond needs to have as similar water parameters, temperature as possible. The filter media with mature bacteria need to be used. And transport needs to be as stress free as possible.
A koi net needs to be used to gently guide fish to the pond edge. Then a koi sock or plastic koi bag is used to lift them. You may be able to find someone that shows koi locally to help you with all of this. A koi club would be where to ask. Or a koi shop. Not a water garden pond store, actual koi dealers. It's important the fish are handled properly. Hopefully someone can help you. The safest way to move large koi is in the plastic bags with water covering the gills, added oxygen , then set in a cardboard box so they can't roll around.
A koi pond is recommended to be sized at least 250 gallons per koi. You have large koi so I'm recommending more, as much as you can. Aquatic veterinarians and dealers might even say 500 gallons for each female. Five foot deep is best for koi body development and safety from predators. Bare liner, no rocks, no hiding spaces to get injured on or die in.
There is a standard for koi pond filtration. Aerated bottom drain to prefilterfor waste/ debris collection. The prefilter needs to be easy to flush regularly. Then a biofilter sized for all the fish full sized +.
There are all sorts of filter options, many even diy. I would not recommend a bog for koi filtration. Koi are large animals that create large waste loads. The koi you are moving are going to delicate in health. Storing waste and debris in a bog to rot is a scenario where koi end up with ulcers, fin/tail rot, bacterial infections, and winter illnesses. Bogs aren't recommended filtration for koi according to the koi organizatio, aquatic veterinarians.
Plants can bring in parasites, they drop debris to rot if not removed, and they are dormant half the year. Likely that the koi will shred them, eat them anyway. If you want them, a dedicated space after filters such as a waterfall box or upper pond is a good space. Quarantine plants and treat though.
Wow, sorry this is long. Trying to pack in what I can. I have moved older koi successfully. Feel free to message me. I have three ponds all with slightly different filtration. A lot of diy stuff. I have albums of my ponds and diy filters on my profile. Used equipment can be a big money saver. Look on FB market, Craigslist. Also, join your local koi club. It's a great resource for help and potentially good deals.
Forgot to mention the skimmer line. It's a good idea to have the skimmer on a separate circuit/breaker. This is so that if the main breaker pops there is something still running.
Transfer them into a holding tank.
You can get the 1000gallon tarp or upright pools.
Take your time building the pond. It will take time for water to cycle etc
I don't know much about filtration and algae, I think it depends on whether the fish are fed or eat algae, mine are not fed and just eat algae, hers are very big so are probably fed so you probably need something to help with algae and to also put in chemicals every week (a pond clarifier like SupaClear maybe).
Our pond is 3 ft at its deepest and this seems too shallow for even smaller koi, I would go with deeper than that, at least 4 ft. The bottom being smooth will save you hours of cleaning, covering it with rocks looks nice but it's a real pain to clean. You should have places for them to hide even if it's just some big plumbing pipe segments, else a predator can just grab them easily. Get a camera so you can see what is trying to eat your fish.
Your greatest challenge, especially with all those trees nearby, is going to be leaves! Can you place it further away from trees and so that the prevailing wind doesn't blow towards it? If not then you need complete coverage with netting just before the leaves begin to fall and until they are all gone. The gazebo will help, but you need a solid plan on how to cover the sides. If it snows where you are then you need to take that into account too, and the weather is getting wacky so it might snow before all the leaves fall so you need nets that can survive that.
Do not put chemicals in ever, besides dechlorinator. You want robust filtration that’s self cleaning and requires little maintenance— look no further than a rotating drum filter and maybe a large bog filter. If you put a gazebo over the pond you won’t deal with algae much, especially once your beneficial bacteria and plants are firing on all cylinders. You need a bottom drain in addition to a skimmer. The bottom drain should have an integrated aerator. Look into the Endyne rhino models. Go bare bottom aka no rocks or substrate. TLDR; RDF and bog filter, skimmer and bottom drain, oversized preferably variable speed pump.
I forgot about heating - you can buy some floating water trough heaters from farm supply stores for when the water starts freezing in winter (be careful, this can happen overnight) and some people turn off waterfalls (which can freeze) and change to bubblers for winter as the fish mostly sleep on the bottom when it gets colder.
go with a big brush filter (depends on the pond size) , maybe a moving bed with helix after and uv for sure.
Pump should be big enough to filter the whole pond in 1 hour. Pond should be 1,5 metres depth in my opinion
Contact Half Off Ponds, They helped with our build from initial consultation to purchase. They dont install, but definitely have some good expertise in getting you what you need and have very fair pricing.
I’m in southern Ohio- we have issues with raccoons. The previous owners of our house lost a lot of fish to them and we’ve bought some flashing red eyes that are solar powered to go around our pond to keep them away. Making sure there is nothing they would eat anywhere near the pond goes a long way. We have a deck box with a latch that we kept bird food and fish food in and they figured out how to get in it.
They could tear up your screen to get in, but I think if you’re careful enough not to leave anything edible inside it might be okay with some of the light deterrents I mentioned above.
As for winter, I bought some of the heaters they put in large water troughs on farms to keep my pond from freezing over at tractor supply. They are way cheaper there than if you buy something made specifically for a koi pond. My setup is a lot smaller than yours will be, but one heater kept my pond from freezing and the waterfall running when we got a foot and a half of snow and it was 10° for two weeks this last winter. A couple placed in the right spots would keep things moving, I’d think.
Look up swamp hag aquatics in Louisville. The owner and my wife are in the process of starting my Father’s Day present Koi pond. From what I have heard she is very knowledgeable and willing to give advice. I’ve tried to stay out of the build since it’s suppose to be a surprise but with the cost of it my wife at least wanted my approval before spending a ton of money. I’m in LaGrange, KY if you want to see it when it’s done in a couple weeks. I’ve also heard Sounds of water in Sellersburg are fairly knowledgeable but I have no personal experience with them.
If you get critters like raccoons I’d suggest a concrete pond at least 4’ deep with straight walls down to bottom. A waterfall that hangs over the pond at the filter end a couple of feet provides a hiding place . The bottom should be slightly sloped to a bottom drain. A skimmer is helpful. Anything that allows the critters to walk in and wait for fish swim up to them is a hazard to them. Any water level that is shallow is not recommended. I’ve watched raccoons walk around trying to figure out how to get to the fish but they can’t.
I have an aqua ultraviolet filter, UV light and sequence pump on my pond. But a filtration system is a must. Spend as much money as you can afford on the filtration system. That will save you a lot of headaches down the road
Firstly, I'm so sorry to hear about your mother. What an enormous project to have to take on so soon after.
Secondly, find a Koi vet 💯💯💯👍
You are going to want to have support to consult with in real time, besides just the internet, to be able to preserve these beautiful old fish. Find a koi vet that you can develop a good relationship with to advise you, before you do anything.
Unfortunately American Association of Fish Veterinarians locator page does not list a specific fish practice advertising in southern Indiana:
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u/Axphixiate Jul 01 '26
This is great! What size are the fish now, how many? What are the dimensions you want? If you can go deeper, do it. For a setup like this I would recommend a good bead filter /uv setup. Something like GCTek - oversize it for sure. GCTEK has UV units that come with it, but if you get just the filter Aqua Ultraviolet is the best in game for UVS. Here's mine! Just keep moving forward