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Can Koi Fish Live in a Tank and Survive

Koi Fish can definitely live in a fish tank. Koi are not typically small fish so you must accommodate them accordingly or they will die off quickly. Below I have hopefully given you the information needed to make informed decisions based on your unique situation. So whether you have domestic, Japanese or Jumbo species just remember that your fish are going to eventually be anywhere from 1’ to 3’ long.

Most people don’t have a big enough home to fit a tank large enough for 3’ Koi. Something else to consider if you are wanting Koi and do not own them yet. Koi can live a very long time, some as long as 50 years. So make sure you are ready for the commitment it takes to care for these beautiful fish.

Keeping Koi in a fish tank comes with challenges different than other fish species because of their size and how messy they can be. The reason they are messy is because even though they can live in a tank it doesn’t mean they should be kept in a tank for more than the winter before they get placed back out into the pond.

baby koi fish

Koi Fish Tank Setup

  • Filtration should be on the side of being too much. I firmly believe that having a filtration system large enough to over handle the requirements of filtering a Koi Aquarium will inevitably keep your fish healthy and alive. For instance if you have a 55 gallon aquarium purchase a filter that is rated for 50 to 75gallon setup as an example. This will be the best choice since Koi prefer fast moving water. The filter along with a water current maker will provide that moving water for them.
  • Lighting for a Koi tank should be just like any other aquarium lighting setup. 8 hours is probably good however you could run lighting as long as 10 to 12 hours as long as you give some complete darkness for the fish at a minimum of 12 hours per day. My fish usually get total darkness 8 or so hours and 4 or so hours at room lighting before the aquarium lights turn on.
  • Temperature for a Koi tank should be somewhere in the range of 60 to 65 degrees Fahrenheit which is about 15 to 20 Celcius. Yes Koi can live in very cold water outside but these are not outside fish now however some hobbyists might argue that a chiller would even be better to have on the aquarium set up. I fell that you can try cooler water as in room temperature and if the fish seem to lethargic then try turning the heat up a degree every other day viewing how active them become. Once they seem happier stop increasing the temperature.
  • Highly oxygenated water is preferred by Koi so aquariums with larger water to air contact are better than tanks that are taller with smaller areas at the top of the tank. Adding oxygen to water might help but not as well as having a larger surface area. Try live plants as well.
  • Live plants are a great idea and will help the fish feel like they are outside in a pond. Floating live plants would be good as well but not so much that it blocks out to much light. Be warned though that your Koi might end up eating your live plants. It depends on the specific fish though, some will eat the plants some won’t.
  • Some form of substrate to cover the bottom would be okay as well as adding a few large pieces of wood or rock so the fish feel like they are in their natural habitat.
  • A canopy of the aquarium is a good idea to help keep the fish from jumping out or since they are large fish typically they can splash easily causing water to shoot out of the tank.

Koi fish saying hello

How to Feed Koi Fish in an Aquarium

  • Koi are omnivorous so will eat just about anything. You can purchase specialized food for them and I recommend you do that.
  • I mentioned previously that these fish might eat any live plants in the tank. I have seen some that do not eat plants. Maybe they were getting fed enough or possibly the plants weren’t a variety that seemed edible to them.
  • When feeding just provide enough food that the fish can eat in a few minutes time, anything extra will get scooped up by the oversized filtration system.
  • One thing that might surprise you is the way Koi’s eat. They will dig around in the gravel moving stuff around looking for the fallen food. Your tank water will start to cloud up very quickly if the aquarium has any undesirable excrement and other things embedded in the gravel.


How Many Gallons Does one Koi Fish Need to Survive and Thrive

  • This is a tough question to answer but I will sure give it a try. Because of the possible girth of your koi fish the gallons required will greatly differ.
  • If you think of the requirements for gallons of water required in a pond to house Koi then you are looking at about 1” to 3” of fish per 10 gallons or so of water.
  • Of course now if you are putting Koi in an aquarium in your home unless you only have a few Koi you are probably going to be well over that ration.
  • You will also have to consider not just how big the fish is when you originally put it in a tank but how big it will grow over time.
  • So how much space does a Koi Fish need? Try to follow the rule of thumb for filling a pond and you can’t go wrong.
  • A Koi Fish minimum tank size probably shouldn’t be less than 50 gallons for as little as two or three fish. It doesn’t seem like much but if these fish even just get a foot long each then a 50 gallon might be too small.

koi art work


Be smart and take your time when deciding which fish to bring home for a Koi tank. There are so many different color combinations in these fish that it might be difficult to decide which ones to buy.

Just remember that they live a very long time and they will get quite large so consider these things as well. If you plan on keeping the Koi outdoors in the summer then it might not be as big a deal but I would try to avoid overstocking and filling your Koi aquarium at all costs. These are living creatures that deserve the best of care.

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