|Ranchu grazing on algae|
There is a step further into cultivating algae. The method is called "green water". "Green water" contains a suspension of phytoplankton composed of photosynthesizing algae and bacteria and is achieved by providing enough bright light and nutrition for the algae to grow. The water turns green to brownish and becomes translucent. Ranchu that kept in "green water" feed constantly on suspended phytoplankton. Japanese breeders often say: "ranchu is made with green water". Best shape and health of ranchu can be achieved with this method.
However, raising ranchu in clear water with substantial algae growth, as I do currently, is as beneficial as "green water" method. The fish is free to graze on algae between the main meals. Algae and cyanobacteria are a great source of antioxidants, minerals, vitamins and pigments. In addition, it has positive pro-kinetic effect on digestive tract of ranchu.
With a very plain look of my pond and no substrate or plants, algae and cyanobacteria create an attractive natural looking background for the bright red ranchu!