Pathogenicity and growth rate among the genetic strains of Clarias gariepinus fingerlings in the inbred and the intra-specific crossbred’s population of were evaluated to reveal haplotypes of growth productivity and improved disease resistance in disease challenge cases in fish culture. The fish samples were created from parent stock of the C. gariepinus Benue and Donga Haplotypes then used to create inbred and crossbred fingerlings. The bacteria suspensions were diluted with sterile saline to achieve a final concentration of 1.0 x 10⁷ cfu/ml of inoculum which was then prorated into each 500 ml rearing medium. A total of two hundred and forty individuals comprising of ten (10) from each of the eight (8) weeks old cohort of the inbred and crossbred haplotypes, were immersed in each of the Aeromonas hydrophila inoculated 500 ml rearing media and their replicates in a 30 minutes’ bath. The non-infected specimens (control) of each of the inbreds and the crossbreds of Benue and Donga haplotype were cultured in triplicates alongside the infected specimens in the identical freshwater and feeding condition. Specimens were observed for clinical signs and growth rate during 14 days post challenge cultured period. During the 14-day post-challenge culture phase, specimen were monitored for clinical signs symtoms and growth rate. During the 14-day post infection period, the infected specimens displayed symptoms of A. hydrophila. The disease symptoms include inappetence, swimming abnormalities, pale gill, bloat and skin ulceration and death. The survivors of the A. hydrophila challenge C. gariepinus had significantly higher growth rate than their respective control in both haplotypes. In response to A. hydrophila infection, C. gariepinus haplotypes from Benue and Donga River have the potential for high survival and growth rate. This knowledge is critical for enhanced productivity, brood stock selection, and profitable culture C. gariepinus.