I just had my first look at the leader board. I noticed that some of the people on it don't even have all 7 magic fish. Isn't the object of the game ( I should say official object of the game since there is so many goals in the game) to find the 7 magic fish and save the sacred swamps of Isola or something?!?
I'm the first one to admit I know little about this game but, It looks to me like the leader board is only concerned with $$ earned. Which would be cool if that was the goal of the game. In which case I think that the game should include more aspects of managing the fish store. I.e having to pay rent on the building. Maybe having things to sell other than fish would be cool. You would need to make $$ to buy more stock etc. This would allow for something to do while fish are pregnant.

We sort by money-earned, because we had to pick something to sort by and we went with the Tycoon aspect of the game. If we sorted by the magic fish, then there would be many people tied for first place!

Oh, Yeah..... that Makes sense

I haven't looked at the leaderboard since I saw so many entries that had to be there becuase of cheats or bad code (has that been fixed?) But it seems to me that sorting by total number of species found would be a valid parameter.