The growing need for sustainable agriculture has intensified interest in aquaponics, which integrates aquaculture and hydroponics for efficient resource utilization. This study evaluated the comparative performance of marigold (Tagetes erecta L.) under two aquaponic sub-systems, i.e., Nutrient Film Technique (NFT) and Raft Aquaponics (synonymous to Deep Water Culture (DWC) system , combined with three fish stocking densities (200, 400 and 600 fingerlings of Labeo rohita ). The water volume of fish rearing tanks of NFT system was 3.0 m3 and of DWC 10.0 m3 . The experiment followed a Factorial Completely Randomized Design (FCRD) with six treatment combinations; each replicated twice, over a 75-days period at ICAR–CIFA, Bhubaneswar.
Results indicated that both system types and stocking densities significantly influenced marigold growth, flowering, water quality and economic returns. At 75 day after planting (DAP), maximum plant height was observed in NFT with 600 fish ( average length 36.01 cm); while the lowest was in DWC with 200 fish ( average length 29.06 cm). Flower count per plant was consistently higher in NFT, peaking at 171.94 flowers in the second harvest at 600 fish density. Water quality remained within optimal ranges, though NFT systems maintained higher dissolved oxygen compared to DWC, supporting superior nutrient uptake and growth. Fish survival ranged between 80.4-85.5% across treatments, with slightly better growth recorded in DWC due to reduced stocking density stress. Economic analysis revealed that although NFT required higher fixed capital investment (₹35,000) per unit, it generated greater gross returns at higher stocking densities (₹5,296 at 600 fish SD). However, DWC, with lower capital costs (₹1,800–3,600) per unit, produced higher net returns (₹1,341 at 600 fish SD ), indicating better cost efficiency.
In conclusion, from the study, NFT proved superior for maximizing flower yield and system performance, while DWC (Raft aquaponics) offered a more economical option for small-scale adoption. This study demonstrates the potential of aquaponics for ornamental crop production and provides a framework for optimizing subsystem design and fish–plant ratios.
Keywords: Aquaponics, Nutrient Film Technique, Deep Water Culture, Raft Aquaponics, Marigold, Fish stocking density