The aquatic animals cultivated in China consume about 75million tons of microalgae or microalgae related biological flocs annually, which is nearly three times the national aquatic feed output. Foreign studies have shown that for every 1% increase in microalgae productivity, the global aquaculture output can be increased by 100000 tons. Microalgae have the following characteristics: 1 Endowing aquatic animals with rich body color; 2. rich in carotenoids; 3. improve the nutritional value of seafood; 4. it contains a variety of long-chain unsaturated fatty acids. At the same time, compared with crops, microalgae have obvious competitive advantages, which can greatly reduce the area of cultivated land.

At present, various forms of microalgae products have been used for breeding bait and animal feed. The commercially available microalgae include Spirulina (protein >50%), Chlorella (protein >50%), Dunaliella salina（ β- Carotene >10%, Haematococcus pluvialis (astaxanthin >3%), schizocystis (dha>18%), Euglena（ β- Glucan > 30%, etc. based on the output of dry algae powder, the annual output of the above microalgae is 15000 tons, 4000 tons, 2000 tons, 1000 tons, 10000-20000 tons and 0200 tons respectively. Microalgae have great application potential by substituting soybean meal. In the next 5-10 years, the output of microalgae for feed will increase 10 times.