I grade hard when confining black fingerlings. Additionally, you can suppress a lot of the outright aggression by increasing stocking density.
When a ponds are harvested for LMB fingerlings, the fingerlings are sorted immediately to uniform size classes where there can be as many as four classes. Fish that are abnormally large / suspected cannibals are tossed in with larger fish as forage. Once they are feed trained, interest in eating brethren is greatly reduced. My preference is to bring fry into confined when only 1" as they are still in schooling mode with dad. That also generally before zooplankton bloom crashes.
If all goes well, next spring we will be feed training about 10,000 each of LMB and Spotted Bass for use in experiments. Some can be set aside for photographs showing color changes related to what I do not like to see.
