I have devised a matrix and diagonalized it. The breeding actually follows a very regular pattern for all fish and for all fins. By simply following the row and column to where they meet you can find out what fish and fin each combination will make. The cool aspect of this is that the fins and the fish-bodies are completely independent of one another.
From this, I devised a chart with fins in the columns and bodies in the rows. when placed in the proper order, the fish breed that results is exactly halfway between the two parent breeds. for a copy of this spreadsheet, email
egustafs@purdue.edu