Aquaponic systems are promising sustainable food production technologies that integrate fish culture and plant cultivation. Their performance depends on balanced environmental conditions for fish, nitrifying bacteria and plants. This study evaluated the agronomic performance, mineral composition and essential oil profile of basil grown in a trout-based decoupled aquaponic system. Two cultivation strategies were compared over 60 days: a non-supplemented system relying exclusively on trout-rearing water and a system supplemented with mineral nutrients formulated according to the Hoagland solution. Basil grown without mineral supplementation maintained a healthy appearance and stable physiological status, with satisfactory growth, although biomass remained lower than in supplemented plants. The mineral profile showed comparable nitrate and phosphorus concentrations in non-supplemented and supplemented plants, with nitrate levels of 5.40 ± 0.29 and 5.52 ± 0.29 mg g-1, respectively, and phosphorus levels of 5.46 ± 0.23 and 6.14 ± 0.91 mg g-1, respectively. In contrast, potassium concentration was lower in non-supplemented plants (36.89 ± 3.31 mg g-1) than in supplemented plants (55.56 ± 7.16 mg g-1). Essential oil yield per cultivated surface area remained comparable between systems, reaching 2.96 and 3.09 mL m-2 in the supplemented and non-supplemented systems, respectively. GC-MS analysis showed that linalool (about 24%) was the predominant compound in both systems. Estragole content was markedly higher in non-supplemented plants (21.35 ± 1.46%) than in supplemented plants (5.24 ± 0.68%). These results show that trout-based decoupled aquaponics can support satisfactory basil production while enhancing essential oil accumulation and modulating aroma-related composition, making this approach a promising sustainable strategy for aromatic plant cultivation.