If you have a pond that has naturalized with plenty of plants, even without a filter you probably don't really need to feed the fish. Very big ponds tend to settle out and develop a dirt bottom from the leafy debris. Its full of grubs and the bottom of leaves have bugs. The koi also eat roots and some of the plants. The pond we had that was like that got damaged in remodeling so we are starting over with 3 ponds. One of the large ponds does not have a filter but it also has small enough fish so they do not destroy the plants. the pond with the major filter and the very large koi seems to have too much movement to grow large plants, so we have to feed koi for now. You can throw water hyacinth in but they practically gobble them in midair, and nibble on the roots. They disturb the water lilies and uproot them, even moving large rocks. They need to be fed. We throw them raw chicken liver pieces, to get them accustomed to eating something besides dried food.

Interesting. I suspect our pond is way too small, then. From what I've read, I know we have too many fish (five fairly good-sized fish in a pond under 500 gallons, which is what we inherited when we bought the place), but they seem to be thriving, so I don't want to rock the boat.

Thanks for the info!

Also, if you want them to be friendly, you need to feed them. Otherwise they have no reason to come up when you near the pond.

It is really not humane to trap fish into a pond, and then not feed them. Sorry....that's just my opinion. Fish that do not get fed usually start getting large heads and unattractive scrawney bodies....a sign of starvation. Koi ponds do not need to be full of sludge in the bottom...that is a terribly unhealthy environment for them. Its sort of like trapping a dog in a small dog kennel, never cleaning it and expecting him to catch bugs and birds that might visit.

Also, koi need 250 to 500 gallons EACH, so if you have a pond smaller than that you may want to consider finding the koi a new home and getting some goldfish. Or if you want a natural pond that needs little maintenance and no fish feeding, get minnows.

Get your fish a quality koi food and don't throw raw liver to them. that is not a proper koi diet and will foul the water VERY quickly!

I am feeding them, and I agree with you that it keeps them more social. I was more curious than anything else.

I have a number of Koi and no I dont feed them on a regular schedule. I do feed them now and again and they eat pretty good I also have plants they nibble on. I have started feeding them more regularly. I have a pond about 6000 gal and maybe 20 koi about 12-14 inches with a scad of goldies of all sizes. I feed them greens and cereal as well as koi food. I do not want my Koi to come running to the surface and being all friendly as I suspect thats a good way to lose them out here between birds, critters and my dogs Might need to put a small picket fence around the pond just to keep the dogs out. I would say feed the fish if your pond isnt big enough to help support them and if your water quality is good you can aways see them.

The other "predator" you have to watch out for is humans. Caught two of them the other day with a bucket and a net sloshing through the pond!

I DO NOT feed the koi and goldfish regularly for a couple reasons. First, the pond is already a great eco system that's quite large for the number of fish, good depth, well-shaded, with a long waterfall, plenty of natural food, etc. Second, since the pond is in the front yard and therefore accessible by several predators (including the aforementioned humans), I put them at risk if they become too friendly. They eluded their captors brilliantly the other day!

I had the pond serviced recently by a local Koi pond specialist - He said everything looked good and the mostly natural regimen made sense given the way the pond is set up.

Fish are healthier and the pond water is a better quality if you can resist feeding your koi.