
Originally Posted by
nwestwood
In the literature for RAS systems they recommend a maximum of 3 per gallon. I would say no more than 2. This is possible because unlike Tilapia or Trout, they grow slow, and eat correspondingly less per day. Ultimately its the feed input that matters, and your systems ability to break down the output.
With Bluegill, your input will be less and so you can keep more. They are nearly indestructible, will grow in waters 55-80 degrees (12-27C), survive low Dissolved Oxygen and poorer water quality. Sounds like an ideal fish, except it takes 12-24 months to grow a fingerling to 7-8" (considered market size) at around 3/4lb (340g) and you will have every size under the sun. So even when you have market size fish at 3/4lb, only 10-20% of your tank are that big, you net them screen off the biggest for harvest and throw the rest back.
I've been running a 250 (aprox 1000L) system with 100 bluegill, 55 trout, and 65 hybrid striped bass. The bluegill went in 10 months ago, the bass 5 months ago, the trout 2 months ago. The trout were already 4", the others were fingerlings. The trout have doubled in 2 months. The bass are nearly as big, and the bluegill are every size under the sun with the biggest 6" or so.
The advantages are that you can generally get fingerlings or smaller sizes any time of the year, so restocking is not an issue. If you ask for only the bigger ones out of the tank when you get them, you will get a higher percent males, which will grow faster and more uniform.