Nutrition by self is allocated remarkable section of aquatic rearing cost, so desired management of using feed ingredient will help considerably to the breeders of aquatic farms. Spirulina (green-blue algae) is a microscopic single cell which grows in fresh water and has a simple structure but complex composition. This alga is source of various nutrients. In addition, it is an important source of photosynthetic pigments named phycocyanin that has so strong anti-oxidant and anti-inflammation characteristics. Ethanolic extract of Spirulina platensis contain alkaloids, flavonoids, glycosides, tannins, phenolic compounds, steroids and saponins. Also, this alga is noteworthy due to high content of un-saturated fatty acids because high amount of it is composed of gamma-linolenic acid. This alga has lower levels of serum glycerides and low-density lipo-proteins which is considered as a growth promotor, probiotic and immune system booster in fish. Spirulina is a micro-alga with high economical value and is one the algae which is suitable for cultivation in large scale due to high performance of photosynthesis, rapid growth rate and adaptability to environment. Thus, it seems that using Spirulina platensis ii aquatic diet is a valuable strategy to manage the nutrition cost and improvement of the performance of aquatic farms.