I have a pond with all types of fish in it and my goldfish do breed, what you need to put in the pond is some floating pond weed, the babies will stay in there and not many will be eaten by the Koi.

You will be suprised how many babies live as they are jet black and dont change colour for a year or so. I bet we counted at least 30 babies last year!

This is a pic of the type of stuff you need, you can buy it in any pond shop or garden centre.

It grows and spreads like mad, keep thinning it out before your fish breed, once they have done their stuff leave the weed alone until spring. We usually keep a 1/4 of our pond covered with the weed.

http://www.agric.wa.gov.au/ikmp/images/elodea.gif

30? We´ve got hundres here
And we were told they are born black but a lot of them has allready changed colour. They´re still tiny yet the orange and white has started to show in a lot of them.

When feeding time its actually an amazing sight. The entire pond just becomes alive. Theres fish everywhere now.

We do have pond weed in along with other plants aswell. As the pond is fairly new I suppose it´ll be a year or so before its properly spread out but allready some is covered by now.