ratio for bacteria (Gao et al., 2012). The biofloc uptake of the fishwas in-
sufficient to prevent its accumulation; therefore, the biofloc required
regular removal fromthe systemtomaintain the total suspended solids
(TSS) at less than 500 mg L−1
. Whenever the MLSS level exceeded
500 mg L−1
in any BFT tank, some of the water containing flocs was
removed. After settling for 1 h, the supernatant was taken back to the
tank and the biofloc was collected and stored below −20 °C.