I bought the triangle sail to provide shade over my outdoor water feature.  It sits in the direct sun and the algae loves to populate the water.  With the shade from the sail, the algae problem is much easier to control.  I know that it is meant for humans but the fish love it and I love watching the fish so it's a winner all the way around.  Besides that, the sail adds a visual interest to the back yard and is the topic of much conversation.