The present study reflects seasonal algal diversity as a source of food for fishes in the river Ichhamati during October 2021 to August 2022. To understand the seasonal algal pattern in the river Ichhamati, physicochemical parameters of river water such as Hardness, Conductivity, pH, Total Dissolve Solids, Turbidity, Dissolve Oxygen, Salinity, Turbidity, Total Alkalinity, Salinity, Biological Oxygen Demand as well as biologically significant inorganic ion concentrations in river water namely sodium, potassium, calcium, carbonate, bicarbonate, nitrate, chloride were also evaluated during study period. It is found that physico-chemical parameters and inorganic ions in river water play an important and significant role in seasonal algal growth. Throughout the study period it was established that river Ichhamati is not very rich in floral diversity. During study time it was observed that dominant group of algae in this river are Chlophytes, Cyanophytes and Bacilariophyceae, including Species of Oscillatoria Nostoc, Klebsormidium, Spirogyra, Lyngbya, Chlorococcum, Chlorella, Diatoms in all seasons. During spring, summer and monsoon Conductivity, salinity, TDS and hardness of river water is high. Ichhamati contained adequate Na+, K+ and NO3- in summer and monsoon season. High rate of bio-mineralisation during winter was found due to presence of high calcium ion concentration and also high TDS along with high salinity as well as high hardness of river water.