This study evaluated the performance of lettuce (Lactuca sativa) cultivated in coupled aquaponic systems integrated with Nile tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus) under tropical greenhouse conditions. The experiment was conducted across two consecutive lettuce production cycles to assess fish growth, plant performance, water quality, and nutrient dynamics. African catfish exhibited significantly higher specific growth rates (1.08 ± 0.18%/day; p = 0.02) and weight gain (92.38 ± 22.29%; p = 0.03) compared with tilapia. During the first lettuce cycle, tilapia-based systems yielded significantly higher final plant weights (177.6 ± 34.4 g/plant; p = 0.0002), and greater increases in leaf number, weight gain, and absolute growth rate than catfish-based systems. However, in the second cycle, catfish systems resulted in superior lettuce leaf morphology, with significantly greater leaf length, width, and total leaf area. Nutrient profiles differed markedly between systems. In the deep-water culture (DWC) units, total phosphorus (TP) concentrations were significantly higher in the tilapia-based system during cycle 1 (12.39 ± 0.64 mg/L; p = 0.0001), while total nitrogen (TN) concentrations were significantly higher in the catfish treatment during cycle 2 (21.54 ± 2.93 mg/L; p = 0.0007). Catfish-based systems also showed higher levels of calcium and sodium. Despite these differences, temperature, pH, and dissolved oxygen remained within optimal ranges for aquaponic production across both systems. Overall, tilapia-based aquaponics promoted faster early-cycle plant growth and higher initial yield, whereas catfish-based systems enhanced nitrogen availability and improved lettuce leaf structural development over successive cycles. These findings indicate that fish species selection plays a critical role in shaping nutrient dynamics and crop performance in tropical aquaponic systems.

Insect larvae are naturally part of the diet of farmed animals, for instance poultry, pigs, and fish. Thus, the black soldier fly, Hermetia illucens (Linnaeus, 1758) (Diptera: Stratiomyidae) has been grown for use as a source of protein in animal feed. Black soldier fly larvae (BSFL) feed on various organic materials and bioaccumulate the nutrients obtained from the organic materials. This results in BSFL with protein content ranging from 25 to 60% depending on the type of organic material fed. Feeding strategies customized for optimizing BSFL growth and protein deposition are essential for sustainably increasing the production of BSFL to meet the growing demand for their use in animal feed. Feeding strategies for sustainable BSFL production should: ensure nutrient utilization efficiency to optimize BSFL growth and protein deposition; use readily available local organic material of good nutritional quality, safe, and acceptable for use in the animal feed industry; ensure economic and environmental sustainability; and adhere to existing legislature. While substantial information on feeding BSFL is available in different data sources, the literature mainly focuses on increasing BSFL production without integrating sustainability issues, especially economic and environmental sustainability. The objective of this review was to synthesize and consolidate existing information on feeding strategies for BSFL production from different sources and point out sustainable feeding strategies, existing knowledge gaps, and aspects that require further research. The purpose of the review is to provide information on feeding practices for the sustainable production of BSFL to meet the growing demand for BSFL in animal feed. This will contribute to improved food security, environmental management, and job creation. BSFL can feed on mixed organic material food sources more efficiently, reducing the volume of the food by up to 72%, while bioaccumulating the nutrients better than when feeding on individual organic sources such as fruit or vegetable waste.