The invention discloses an alga control method for a freshwater environment based on cultivation of barracudas and mullets, relating to a
water treatment method. Aiming at solving the problem that
algae can not be stably and thoroughly controlled in a eutrophic
fresh water body, the method comprises the following steps: at least introducing one species of estuarine / marine fishes, such as barracudas and mullets which can only be propagated in sea water, and carrying out
desalination processing before cultivation to enable the barracudas and the mullets to be adapted to a freshwater
living environment, wherein the mesh size in the large
water body ensures whether the cultivated fishes can escape; dividing or mixing according to different ages, carrying out culture in
enclosure in girds by meshes, and simultaneously cultivating and propagating silver carps, bighead carps, other local fishes and local
shellfish; and propagating local common aquatic plants. Thus, the fishes can be fed on the
algae in a filter-
feeding mode and simultaneously swallow
detritus substances, thereby achieving the purpose of thoroughly purifying the
water environment. By harvesting the cultivated and propagated
aquatic organisms to remove
nitrogen /
phosphorus nutrients in water and
humus in
bed material from the
water body, the method disclosed by the invention greatly improves the
water quality of the cultivation
water body.