The measured DO concentration inside the
fish-tanks at the normoxia and hypoxia treatments were 80% (6.9 ±
0.2 mg L−1) and 40% (3.5 ± 0.4 mg L−1), respectively. During the
trial, the water temperature was at 27 °C and pH at 6.7. Total ammonia
nitrogen (TAN) was remained below 2 mg L−1 in both systems.