Hi Bobby ,
a dam in capalaba ok maybe you do 8)
sorry being ??? Depends on depth of dam and volume of water1 meg 4 meg or greater / ability to maintain oxygen ?
i would browse DPI web for answers and they would also have list of aquaculturists near you / i believe for YB around Ipswich area/ a dam reasonable size of say 4 meg could handle 30 or forty larger yb's comfortably/ without going intensive farming
cheers Peter