How do I tell if my fish is a boy or girl?

Question

I have two Dalmation Mollies, and I was just wondering how I could tell if they were a boy or girl.

One of my Dalmation Mollies looks pregnant. She is fat. She has a long fin under her. But my other Mollie is chasing her and has a short fin underneath.

Answer 1

Mollies are livebearers, so they are easy to tell the gender. Males have a rod-like fin called a gonopodium directly beneath their dorsal (top) fin. Females have a "real" fin, not rod-shaped.

~ZTM

Answer 2

the boy seam to chase the girl around alot, and the boy usually always under the girl fish, or you can look under the dalmation molly if it have a long stick thing under it's belly it's a boy, and if it's has a flat fin under it's belly it's a girl fish

Answer 3

Bang is almost right.

Males have a long, cylindrical gonopodium which is the fin on the belly right before the tail. On females, this fin is in the shape of a triangle.

Answer 4

Here are some pics, it's easiere to show then to explain

http://www.bbayaquariums.com/black-molly.jpg (Female)

http://www.exiledplanet.org/images/fish/black_molly.jpg (male)

Hope that helps
Good luck

Answer 5

Anal Fin Is Longer with boy girls have more gurth

Answer 6

if there the same as guppys then the females arent as colorful as the males

Answer 7

girls have a bigger fin where the poop comes out.

Answer 8

i think the males have more colour on them....

Answer 9

does it matter?