thats way overstocked.... unless you plan on major expansion immediately (each growbed will take time to cycle up, and won't be converting ammonia until it cycles)..with a new system of that size, the most i would go would be 20
fingerling fish consume anywhere from 7-15% of their body weight daily, adult fish about 2-4%,
smaller fish are usually more active as well (the act of "breathing" the water, gills breath out ammonia)
when you first get your fish, monitor your system closely, and feed lightly
and if you don't already have an aerator, get one