I have used two ways to control algae in my one acre pond without chemicals. The first was using 20 KOI, 6 Israeli carp. These are the algae eaters. I had enough bass that controlled the KOI & Israeli carp that I never seen one extra of these type of fish over many years. In addition to those fish I had grass carp to keep the excess water plants down. This is what that pond looked like.
When all of those fish were killed off in winter kill I redid my pond for algae control. It's all done with plants. In this makeover pond I have lots of plants, 7 grass carp for some underwater water plant control. I also have snails, clams and fathead and shiners minnows. the bottom of the pond is not disturbed with any bottom fish. The water is extremely clear. This pond bring in lots of wildlife.
