The freshwater culture system consisted of 33
aquaria (90 L each) provided with flow-through
well water at a rate to achieve total exchange of
volume every 6 h. Submersible heaters (Visitherm
150 W) were used to maintain a constant
temperature of 27 6 2 C. A blower provided air
that was distributed to each aquarium through
a ceramic airstone. Drain stand pipes (1.27 cm
diameter) were covered with a 500-mm-diameter
nylon mesh, and the top of each aquarium was
covered with clear Plexiglas to prevent escape
of prawns.