I recieved a couple of requests for information on how commercial raising of Danio Rerio takes place. So here is some information on the techniques used by Scientific Hatcheries, my father's company. Any questions can either be asked of me and I will forward them, or you can call him directly. (Dallas Weaver, 714-890-0138). All our fish are grown using closed cycle systems. Our tanks are 5" diameter/3" deep fiberglass tanks. On a fish the size of Danio Rerio, we will have anywhere from 100 to 300 thousand fish in a tank.
Hatching:
In order to hatch large (100-200 gram quantities of eggs), we use a
McDonald jar or equivelent. (A McDonald jar is a cylinder which has a
standpipe going down for water.) A layer of 90 mesh silica sand is added to
the bottom, enough to fluidize to 1/3 the size of the cylinder when the flow
is on. Then the eggs are added. They remain fluidized. When the larva
hatch, they flow out the top of the McDonald jar and are captured and
transfered to a large tank for growout.
Feeding:
We start our larva on a mixed protizoan culture. I understand that
others use a paramecium or rotifer culture. Afterwards, they are fed
artemia noplei. Later, Silver Cup Salmonid feeds are used for the growout to
adulthood. All feeding is done using automated feeders which are computer
controlled.