Influence of different hydroponic units on fish and plant performance and water quality in a snakehead fish-mint aquaponics system

Abstract This study was done to assess the effect of two hydroponics cultivation (media bed (MB) and floating raft (FR)) on the performance of striped snakehead fish (SSF) ( Channa striata Bloch, 1793) and mint ( Mentha arvensis Linnaeus, 1953), and water quality parameters in the aquaponic system. Fish were cultured at a density of 500 fingerlings per m 3 for 130 days. Mints were planted at densities of 40 and 34 lettuce m −2 in the MB and FR treatments, respectively, and had two cutting harvests. During the experimental period, levels of most water quality parameters analysed in the two treatments were in the optimal range for SSF and mint. After 130 days, all the growth performances and survival rates of fish in the FR treatment were higher than those in the MB treatment, but these differences were not statistically significant ( P > 0.05). Fish growth performance was similar to those reported in other RAS and aquaponics studies, whereas FCR was lower. For mint, the plant height and diameter in the MB were significantly higher than those in the FR, but the fresh biomass in the FR was significantly greater than that in the MB ( P < 0.05). In general, these results implied that the FR unit is more effective than the MB for culturing SSF ( C. striata ) with mint ( M. arvensis ) in aquaponics.