The Koi fish is one of the most popular ornamental fish in the world. They are colourful and graceful fish, that can be kept in a variety of ponds and large aquariums. Koi are considered good luck in Japan and are often given as gifts.
Pond algae can be an important part of a healthy aquatic ecosystem. They serve as food for fish and other aquatic creatures, and as a substrate for plants. Pond algae can also provide oxygen to the water, and help clean the water.