Integrated Aquaponic Co‐Culture of Nile Tilapia and African Catfish: Effects on Plant Yield, Fish Growth, Nutrient Profile, and Heavy Metal Accumulation

Abstract

A 106-day experiment was conducted to evaluate the co-culture of Nile tilapia (<i>Oreochromis niloticus</i>, 20.4 ± 0.29 g) and African catfish (<i>Clarias gariepinus</i>, 19.8 ± 0.46 g) in an aquaponic system using eggplant (<i>Solanum melongena</i>) as vegetable specie. Fish were stocked at an initial biomass of 10 kg·m^-3 with five different Nile tilapia: African catfish stocking ratios: 2:8 (TC₁), 4:6 (TC₂), 5:5 (TC₃), 6:4 (TC₄), and 8:2 (TC₅), totalling 100 fish per tank. Results showed no significant differences (<i>p</i> > 0.05) in eggplant yield, Nile tilapia growth performance, or survival rate among treatments. However, African catfish growth performance declined with decreasing proportion of catfish, with a statistically significant difference observed only between the highest (TC₁) and lowest (TC₅) catfish ratios. The lowest survival rate (90.0%) was recorded in TC₅. Proximate analysis revealed no significant variation (<i>p</i> > 0.05) in the nutritional composition of either fish species across treatments, and heavy metal levels in fish flesh remained below toxic thresholds. Water quality parameters remained within optimal ranges for both species and did not significantly influence fish growth. These findings support the feasibility of co-culturing Nile tilapia and African catfish in aquaponic systems without compromising water quality, yield plant, fish performance, or nutritional value.