Sexing Silver Dollars

[ryknier]

I have two silver dollars, and not like its a big deal or anything, but how do you sex them. Can someone point me to a site, or tell me how to identify them? they both started out at the same size, and now one is significantly bigger then the other. I also have two moonlight gouramis with the same situation, ones bigger then the other

 

[blueturq]

I think that silver dollar males have more red on their bottom fin, whereas the females don't have it as much.