You can have an indoor Koi pond, it enhances the look and feel and can be a great conversation subject. As you know Koi belong outdoors, so you need to mimic an outdoor pond indoors, to keep them healthy and happy.
You will need to regularly change the water because unlike an outdoor pond which has natural ventilation an indoor pond does not. Before deciding where you have your pond inside it is best to keep a window or door nearby to help pump water from the pond.
You will also need to insure the sides of the pond have a wall around it, this will keep any jumping koi in and not in your armchair.
Plus this will keep other pets out like the pet dog who will think he has a huge drinking bowl and the pet cat thinking he has fish on the menu every day.
Also not only will having the pond by windows and doors help with pumping out the water it will let natural sunlight in. The more natural sunlight the better as your Koi will fade in colour. You can buy food additives which help but I suggest you get as much sunlight as possible.
A dehumidifier is also recommended as having water inside will generate a lot of humidity indoors.
Also see Indoor Ponds
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