Terrific pond! You'll have a lot of fun with it. But it is way, way too small for koi, trust me. Koi grow up to 24" in length, and need deep water to swim in, around three feet deep. David is right about the gallon requirement, too. I mistakenly bought my koi a few years ago (he was in a Comet tank), and he has grown to about 12" so far already. Thankfully I found a friend with a huge pond that is willing to take him. I've just been dragging my feet, I hate to part with him. I had better do it soon though, otherwise he will be too big for a ziploc baggy to transport him in, lol.