Did the koi pond have duck weed or watermeal in it? If so, quarantine it for many weeks and make your decision if you want the risk. Plants from nurseries, especially those that cater to Koi ponds, tend to have the duckweed/watermeal pests in them. That can be some nasty stuff to a large pond owner. Koi pond owners think it's nice as it only takes a few minutes to keep it at bay...those that have it in there fisheries talk much differently about it.
