Recirculating aquaponics integrate aquaculture and hydroponics with the aid of microorganisms to ensure a sustainable supply of fish and vegetables. In this study, we designed and constructed a flood-and-drain aquaponic system with Clarias gariepinus as the aquaculture and Celosia argentea, Corchorus olitorius, and Ocimum gratissimum as plant components. Nitrogenous waste from the aquaculture unit was circulated to the plant growth beds, which served as bio-oxidizers of toxic ammonia to nitrate and returned less toxic water back to the aquaculture unit. An evaluation of the growth parameters of C. gariepinus in aquaponics and control fish tanks revealed that aquaponics-raised C. gariepinus gained an additional 205.6% of their initial mean weight, whereas those grown in the control fish tank gained an additional 182.2% of their initial mean weight. The majority (37.5%) of aquaponics-raised C. gariepinus weighed 750 g -1 kg, whereas the highest percentage of C. gariepinus raised in the control fish tank (23.4%) weighed 500 g -700 g. C. gariepinus raised in aquaponics had significantly higher gross feed conversion efficiency and protein efficiency ratio than those raised in the control tank. The mortality rate in the aquaponic fish tank was 0% compared to the 11.43% mortality rate in the control fish tank. There was no significant difference in the nutritional composition of C. gariepinus raised in either tank; however, the aquaponic fish tank had a higher nitrogen retention rate. This study showed that C. gariepinus raised in aquaponics had better biomass accumulation than those raised in conventional fishponds.

This study examined the practicality and sustainability of growing leafy vegetables in aquaponics instead of traditional soil-based farming systems by comparing the physiological growth patterns, nutritional compositions, and phytochemical constituents of Celosia argentea L., Corchorus olitorius L. and Ocimum gratissimum L. grown in aquaponics with those of other conventional systems. The results of this study indicate that the growth and accumulation of biomass by plants grown in aquaponics were similar to those obtained in unamended loamy soil but better than those of plants grown in inorganic hydroponics. However, plants grown in NPK-supplemented soil showed significantly (p<0.05) higher biomass accumulation than those grown in aquaponics. Likewise, C. argentea, C. olitorius, and O. gratissimum grown in aquaponics had significantly higher nutrient compositions than those grown in inorganic medium, and at the same time, similar to that of plants grown in unamended loamy soil. C. argentea and C. olitorius grown in inorganic medium had significantly higher concentrations of the observed phytochemicals than those grown in aquaponics, whereas the opposite was true for O. gratissimum. The three plant species were able to serve as filters for the effective maintenance of nitrogen dynamics in the constructed African catfish aquaponics, while utilizing nitrogenous waste for biomass production.