My dad and I have clipped the upper and lower lobe of the caudal fin just like Bruce, and it indeed works well. (Except, unlike Bruce, I call it a tail fin and had to look-up caudal fin). For us, however, it is not to distinguish fish of a different year class, but to distinguish fish the same age, placed in the pond at the same time, from different suppliers. It is interesting to monitor the growth of fish from one supplier/hatchery against those of another. Both this method and the hole-punch method were discussed at the convention in one of the breakout sessions, and it seems both work very well.
