Well, after you halter break them, you stick em in a bag and ship em off to a show to be judged against the current standards. The fish are assumed full points and demerited based on faults.
The fish are judged on several considerations - finnage, colour and deportment.
There are several types of finnage, and each has their own standard. Two staples are longfinned Halfmoon and Shortfinned Halfmoon. Whether long or short finned, they have to have a full 180 degree caudal(tailfin) spread, balance, proportion, strong fin rays, and clean fin edges.
Balance is the ability to draw a line around the outer edge of their fins and have the line be smooth and free of kinks and/or bumps.
Ideal proportion for longfins is 2/5-3/5 caudal length - body length. For shortfins, is
1/3 caudal length - 2/3 body length.
Here is a longfinned one I owned:
This is a short-finned one I wish I owned:
Just for comparison, here are some 3D models we developed as standards for short and longfinned respectively:
Because they are fighting fish, deportment is very important. This means the fish must be reactive, aggressive, and able to swim freely & uninhibited by their fins. Of course, they never fight...that is illegal. Here is a pic of a recent show set-up: