The study investigates comparative changes in morphometric, meristic and haematological values of triploid and diploid strain of Heterobranchus bidorsalis with a view to establishing differences and comparative adaptability between the two strains. The experiment was carried out inside net hapas submerged inside 1 × 1 × 1.2 m2 concrete tank where diploid (2n) and triploid (3n) fish were reared. Each hapa net contain 45 post fingerlings of the same genetic makeup. 10 post fingerlings of diploid and triploid strains of H. bidorsalis with average total length between 11.2 and 12.8 cm and 12.2 and 14 cm respectively were collected for morphometric and meristic parameters. Blood samples were also collected and analyzed packed cell volume (PCV), haemoglobin (Hb), white blood cell count (WBC), red blood cell count (RBC), mean cell hemoglobin concentration (MCHC), platelet, and mean cell volume (MCV) values of triploid and diploid fish were analyzed. This study shows the superiority of the triploid H. bidorsalis over the diploid strain. It also indicated that morphometric and meristic indices are the best parameters to characterize post juvenile diploid and triploid H. bidorsalis while haematological indices is not a better indices for characterization of juvenile diploid and triploid H. bidorsalis.Key words: Heterobranchus bidorsalis, diploid, triploid, morphometric, meristic, heamatology
