Ive read this thread and have seen so much conflicting information it is unbelievable.
First of all, i was linked to this thread from another site, i read everything, including the general question here, and just had to chime in.
Im not going to consider my answer the end all be all, and i certainly encourage you to do personal research before following any of the advice you find here, and directley from myself, before coming to any sort of final conclusion on your indoor pond venture.
Second, allow me to Introduce myself.
My name is Mycol (Michael) and i work for Lilypons Water Gardens in Buckeystown, MD. I am an aquatic plant and fish specialist. Ive built hundreds of ponds, varrying in size. Ive also handled very many different kinds and sizes of fish and other common aquatic animals. Shebunkins, Israeli Koi, Japanese Koi, Domestic Koi, all ranging in size from 3-4 inches to up to 3ft.
Finding a koi much bigger then 3ft is next to impossible, although they CAN get that big, they are rare. They can live to be 100+yrs old...and to be 3+ Ft, they gotta be pushing atleast 90.
Fish, commingly, grow to the size of the pond. Putting a mature, 12inch+ Koi, in a 500gallon pond, is not going to make it shrink... in fact, it can harm the fish if it is in contest with others. Ideally, they need 1000+ gallons to be comfortable...a mate, wether of same sex or not, is preferrable, as they are the kind of fish who associate with eachother. When i say they grow to the size of the pond, i mean that a 3-4inch Koi is not going to reach more then 12 inches in its lifespan, in a 500gallon pond. They grow to the size, based on amount of available oxygen, and nutrients in the water (Food) for them to eat. Oxygen = Digestion
The less oxygen, the more food goes to waste and is essentially, Pooped out.
Having an indoor pond can be very simple, and enjoyable.
Think of it, and treat it, like a fish tank. If you plan on having plants, i suggest having lighting inside to give the effect of the sun. Especially if you have water lilys. They will bloom indoors, all year round, if the temperature is kept at a constant 77-80degrees. Also, keep water movement to a minimum, you'll get more lily blooms that way. The plants give the fish (Koi, in your case) a sense of security, they wont feel the need to swim erratic and throw themselves out of the pond. But for the first few weeks, keep an eye on them. Sit on the edge and hold food in the palm of your hand...allow them to smell it and within a week, they will be trained to come to you for food. Thus making them very friendly fish, and not easily startled.
Evaporation will occur, but not bad, if you keep the indoor temperature at a normal 69-72deg. Keep the area very well ventilated, windows open if you can, and have a good under floor filter system setup, you can even use a regular Bio Filter and incorporate it into your waterfall if you want one. They can be easily hidden if you'd like the enjoyment of an indoor landscape surrounding your indoor pond.
If you have anymore questions, feel free to contact me...and if your ever in Buckeystown, MD, stop by Lilypons, i'll give you a nice 30% discount!
Mycol
MikeMain@onlineracin.com
