This study investigates the effect of anticoagulants on haematological parameters in thirty (30) feral (wild) and thirty (30) pond cultured African catfish (Clarias gariepinus). The anticoagulants used in this study were lithium heparin and sodium ethylenediaminetetraacetic acid (EDTA). Red blood cell (RBC) count, packed cell volume (PCV), hemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), total white blood cell (WBC) count and differential count were determined. No significant differences (p >0.05) were observed in the total RBC, WBC and MCHC values in the feral and pond cultured fish. In the pond cultured African catfish, the neutrophil values were significantly higher (p =0.001) than those of the feral African catfish irrespective of the anticoagulant used. The values for PCV, Hb, lymphocytes, eosinophils, MCV and MCHC of the feral African catfish were significantly higher (p <0.05) than those of the pond cultured African catfish irrespective of the anticoagulant used. The monocyte value for the feral fish was significantly higher (p =0.041) when EDTA was used as the anticoagulant. This study therefore concludes that both anticoagulants could be used for haematological evaluation of fish blood. Also, the habitat and environmental conditions should be taken into consideration when analyzing blood samples in fish.