The aim of this investigation was to evaluate the effect of chromium on hematological and biochemical parameters in Epaulet Grouper, Epinephelus stoliczkae of Chabahar Bay and Gulf of Oman by ecological and experimental tests. Spatial evaluation of ecological test results showed these parameters had significant difference among some sampling sites. Examination of hematological and biochemical profiles on Epaulet Grouper was performed after 0.5, 1, 7, 14, and 21 days of chromium exposure (3.6, 7.31 and 14.6 mg/L). Experimental test results of chromium induce indicated the significant decrease in MCV, MCH, neutrophils, basophils, plasma protein and significant increase in MCHC, lymphocytes, monocytes, eosinophils and a biphasic trend in Hb, Ht, RBC, WBC, and glucose (p < 0.05). Cellular and nuclear axis, cytoplasmic volume, cell and nuclear volume, and surface area were significantly different for ecological and experimental results (p < 0.05). It was concluded that these parameters are sensitive in monitoring the toxicity of chromium concentrations.