The purpose of this study is to examine the effect of nitrogen and phosphorus ratios (N:Ps) on the development of marine algae in fertilized ponds, which are considered to be natural food for Artemia farming. Phytoplankton composition and abundance were determined through qualitative and quantitative assessments. The experiment comprised four treatments, in triplicate (i.e. treatments 1, 2, 3 and 4, with ratios of N:P = 3, N:P = 6, N:P = 9 and N:P = 12, respectively); fishmeal (2nd grade) was used at the rate of 30 g m-3, while urea and DAP were combined at the rate of 6 g m-3, with urea and DAP accounting for 4.93 g and 1.07 g, respectively. Study results showed that the average density of algae varied from 637x103 to 2,434x103 cells mL-1. Algae density produced by the N:P = 6 treatment was the highest (i.e. 2,434x103 cells mL-1), and there were statistically significant differences (p < 0.05) among the treatments. In total, 52 algal species were found: 21 belonging to Bacillariophyta; 21, to Chlorophyta; 7, to Cyanophyta; 1, to Dinophyta; and 2, to Euglenophyta. Additionally, algal compositions were 38, 32, 35 and 27 species observed in four different treatments (N:P = 3, N:P = 6, N:P = 9 and N:P = 12, respectively). The dominant genera were typically Nitzschia, Thalassiosira (Bacillariophyta), Tetraselmis (Chlorophyta) and Oscillatoria, Lyngbya (Cyanophyta). As results demonstrated that algae developed well at treatment N:P = 6, this could be considered a suitable treatment for fertilizer pond management applied in Artemia farming.