Pond and koi problems

I just got some koi from a friend and now my pond is a muddy mess and stinks and my water lilies are dying. Do I need to clean the whole thing out and start over?

Pondlady sez: 
First of all, your koi are eating your water lilies. And the fish waste is making the pond stink. If you give the koi away and get a couple of plain goldfish and then balance your pond ecologically, you will have a clean pond that is relatively maintenance free. Yes, you do have to clean it out and start over. Sorry.

If you wish to keep the koi, you must add a biofilter and feed your koi.