2. Eight tissues of algae become "fat". After the algae died and rotted, the oil dissolved in the water and then surfaced. Grease attached to aquatic plants, tank walls, etc. when fresh water is injected. Will be washed out and then surfaced, resulting in oil film on the water surface. ?
3. Oil produced by microbial residues or old wastes, residual bait and organic substances. The oil film is the most serious when there is no flow on the water surface. ?
The filter material in the filter is too dirty, so the oil overflows.
Extended data:
Koi fish, also known as the original species of Fei koi fish, is the red carp (Cyprinus carpio). Red carp, as an ornamental fish, was very popular in Ming Dynasty. It is said that koi fish originated from koi fish, Longzhou, Xingguo Red Carp and Hangzhou, Zhejiang, and was introduced to Japan from China in the early days. After long-term artificial cultivation by the Japanese people, there are now more than 100 varieties.
According to documents, koi fish was first raised and watched by Japanese nobles in a pond, which is rare for civilians. Originally called Fei carp, color carp and flower carp, it was renamed koi fish after World War II. 1973 As a friendly envoy of the Chinese and Japanese peoples, japanese koi settled in China. Japanese boys' day also hangs the "carp flag", which shows the Japanese love for koi fish.