Read the passage below and summarize it using one sentence. Type your response in the box at the bottom of the screen. You have 10 minutes to finish this task. Your response will be judged on the quality of your writing and on how well your response presents the key points in the passage.

The metabolism of koi and goldfish is controlled primarily by water temperature. As the water cools, pond fish require less protein in their diet. When koi and goldfish are fed high-protein food in cool water, the excess protein is excreted as ammonia from the gills. The microscopic organisms that make up the biological filter (and consume ammonia) also slow down in cooler water. Improper seasonal feeding can lead to a build-up of toxic ammonia, which stresses fish and reduces their winter survivability. 

When the water temperature drops to approximately 65° F, start feeding with Spring & Autumn Pond Food. This type of fish food is better suited for the dietary requirements of pond fish in cool water and won't pollute the water with excess ammonia. Some water gardeners continue to feed their fish until they no longer come to the surface. 

I stop feeding my pond fish when the water falls below 42° F. There is no need to worry about "frozen fish" if a section of the pond is at least 18 inches deep. Pond fish will seek the deepest part of the pond and over-winter there until the water warms in the spring. If your pond is less than 18 inches deep, the fish may freeze during a harsh winter. Check with your local pond supplier if you live in an area with harsh winters.