The way these coppernose spawn I have fear off not being able to control them in 1/4 pond but I sure do like them!
Any chance you could bucket stock single-sex CNBG into the 1/4 acre pond?
If you sexed them from your main pond at the height of the spring spawn you might get 100% correct identification.
The 1/4-acre pond could then be your trophy pond. A limited number of fish should grow very rapidly.
Put in 10-20 each year for ladder stocking, and also catch and eat 10-20 of the big ones each year to balance the pond.
It might work until you eventually make a misidentification. At that point you could put in four female LMB and run a different kind of trophy pond!
