You've got to do your own growing, no matter how tall your grandfather was.
~ An Irish Saying
The technique of grooming the BBR is likened to that of a Sumo wrestler - they are nurtured to epitomise strength, power and agility. The Japanese technique of grooming BBRs and Sumo wrestlers entails high quality food and good exercise as well. It is no coincidence that the ranking of Ranchus in the AJRS takes after the ranking of the Sumo wrestlers.
Ask any Japanese Ranchu Master and they will say that the bloodline is the most important criteria to making good BBRs. Besides the bloodline factor, grooming is what we do by varying pond space, amount of feed, type of feed, stocking ratio, water change regime and environmental conditions.