In fish ponds, algae can sometimes take over and kill the fish. Keep your pond clean and free of excess algae that will make the pond green and unhealthy for the fish. All ponds need some algae to host bugs, frogs and fish, but not too much. Learn how to prevent algae growth so that your pond stays clean and healthy.
Keep a 20-foot rim around the pond that is not mowed. This will help keep the nutrients in the ground from getting into your pond. The weeds and grass will utilize the nutrients, so they will not make it into the pond.
Avoid putting down fertilizer near your pond. If the fertilizer enters the pond, it will increase the nutrients in the pond and cause algae to bloom and take over.
Keep septic systems and ponds far apart from each other. Broken-down septic waste travels through the ground. The further it is from the pond, the better.
Prevent birds from swimming in the pond. Bird droppings will cause nutrients in the water, and provide a breeding ground for algae.
Remove any dead fish in the pond. As the fish rot and decay, they leave nutrients in the water that will cause the algae to increase.
Add chemicals to the fishpond; talk with a professional about how to do this. If you add the wrong type of chemicals, or the wrong amount, you can kill off your fish. A local university or agriculture outlet will offer their help free of charge.