Macrophytes Used as Multifaceted Benefits Including Feeding, Bioremediation, and Symbiosis in Freshwater Aquaculture—A Review

The utility of macrophytes in freshwater aquaculture is diverse. We review the benefits of macrophytes in aquaculture into broadly three useful perspectives: (i) Feeding, (ii) Bioremediation, and (iii) Symbiosis. Macrophytes are used as direct food by herbivores for their potential nutrient values with a maximal protein content of 35% (D/W basis) and as ingredients for fish feed preparation with optimal 50% protein inclusion to reduce feed cost in commercial aquaculture. Macrophytes are used for wastewater treatments to eliminate contaminants, including As, Cu, Cd, Cr, Hg, and Pb, to 99.9%, and to reduce BOD (Biological Oxygen Demand) to improve water quality. Intake of remedied wastewater into aquaculture enhances water productivity through phytoplankton growth. An estimate is that 1.0 L of remedied wastewater, particularly sewage effluent adds an average of 0.05 g N & P and 0.99-L freshwater into aquaculture to yield an average of 0.309 g fish. Macrophytes are integrated with fish in commercial aqua-farming. Plants and fish are farmed together in aquaponics. They are used as substrates for some commercial fish species to lay eggs in farming. They are raised with ornamental fish for benefits in aquariums. Nevertheless, extensive studies are required to harness more benefits from macrophytes.