DOn't know about the Carp, Black Moore, or Koi...but I'm guessing you may be able to Google and find it.
Guppies, Mollies, and Swordtails are all the same.
Kissy's Absolutely right about the "Sword" on the Male Swordtails. But they also have a Gonopodium. I believe all livebearers do. Mollies, and Guppies don't have the Sword, so...
If you look on the "Bottom side" underneath the fish, you will see either a regular old Fin, or a "gonopodium". It looks like a fin that is all bunched up into a "roll", and extends towrds the back of the fish. These are the males. The females just have a fin.
Here's a Pic of a Male Swordtail...the Guppy and Molly Males will have the same look on the bottom:
Here's a Female Swordtail...notice, No Gonopodium, just a Fin.
Images Courtesy of aquariumfish.net