Another species of carp that is targeted both on the fly and conventionally most people will know as being pets or in someones back yard in a pond. "Koi" carp are becoming more and more popular to chase on the fly and more common in most of the fishing water we find ourselves in due to the obvious cosmetic appeal that these colorful fish present to the angler. They will also put up a very hard fight, at times stronger and longer lasting than a common or a grass carp.
Although a lot of the time the koi can be skiddish and very wary of people making them very hard to catch especially on the fly. If they had previously been in someones pond and dumped into the water system or the lake you are fishing then the sight of people may not spook them. Regardless approach them as though they were really skittish and if they are used to humans than its a bonus. The same techniques used for the common carp and the grass carp will be useful as well when chasing carp. Due to the usual bright coloration that the koi have, they are a bit easier to see even in muddy water. The same leading techniques or the drag and drop will be the most useful in catching koi. The fly's that are used will be more focused on the glo bug area, pellet flies, moss and algae flies.
As with the other types of carp in the public lakes that have foot traffic and waterfowl the fish are used to eating the scraps of what people feed to them. So the bread flies and the pellet flies should hold a permanent place in the fly box when chasing koi. Focus on the lakes and local park ponds rather than the river systems as they will be more often found in slower moving bodies of water.
They will mud in the same matter that the common carp will and have the same area in front of them to place the fly where they will take it. The koi should be fished nearly the same way as in fishing for common carp but treated with the spookiness of the grass carp.