Azolla (Azolla filiculoides) as water treatment of Nile tilapia (Oreochromis niloticus) aquaponic system

Abstract

Aquaculture industry faces challenges such as environmental deterioration, water scarcity, limited land, and high input costs. This study investigated the eight-week growth performance of Nile tilapia Oreochromis niloticus at two fish sizes (2 or 3 fish, 20 g each per tank) and the growth and nutrient removal efficiency of Azolla filiculoides at three Azolla densities (0, 0.04, 0.08 g/L) in aquaponic systems (APS). The experiment used a 2x3x2 factorial design with six treatments. Results showed that FS and AD did not affect tilapia growth performance. However, higher FS and AD increased Azolla weight increment (WI), with treatments containing three fish showing 24.11% higher WI than those with two fish. Nutrient removal efficiency was higher with Azolla, and significant interactions between AD and time (T) on ammonia (NH3), nitrate (NO3-), and total nitrogen implied that the growth of Azolla depends on the nutrients present in (APS).