Red fillet results in a profit loss for catfish processors and producers alike; however, neither the cause nor the abundance of red fillet has been studied extensively. Therefore, an assessment of red fillet in the catfish industry was conducted along with studies subjecting catfish to poor water quality and inoculation with Aeromonas sobria. Within every catfish harvest, 0.12% of fillets were rejected due to blotchy red coloration. Histology revealed congestion of erythrocytes indicating internal hemorrhaging, and A. sobria was isolated from 63% of all red fillets compared to 28% of acceptable fillets. Acute exposure to poor water quality did not produce red fillet in catfish despite high stress levels and mortality rates (22%). Inoculation with A. sobria did induce red fillet with similar coloration to red fillets obtained from catfish processors.