species such as shrimp and tilapia that are filter feeders are ideal for such
asystem(Azimand Little, 2008). In practice, however, problems still exist
in using a BFT system to culture fish. Organic carbon must be added to
the water to maintain a C:N ratio of N10. Furthermore, implementing a
systemformixing and aerating thewater,which raises energy costs, is re-
quired tomaintain an active biofloc in suspension and tomeet the oxygen
demand of elevated water respiration (Avnimelech, 2012; Hargreaves,
2013). Particularly, the suspended solid content in BFT is typically greater
than 500 mg L−1
, and excessive solid concentrations can clog the gills of
fish or shrimp, which affects their growth and welfare.
The idea of conducting the current study is based on the reality that
both the BFT-aquaculture system and RAS model can be used to culture
fish in indoor closed water. If successful, BFT might be a promising alter-
native technology for a conventional RAS in cultivating both filter feeding
and detritivorous aquaculture species. An experiment was conducted
to evaluate genetically improved farmed tilapia (GIFT) welfare in BFT-
managed tanks, to compare dissolved inorganic nitrogen dynamics, to