Can't tell the gendre of my mollies!!

[pisces11]

I have three black lyretail mollies in my newly set up aquarium and i was wondering about their gendre. I know to examine the fish's anal fin-rounded for females and long and narrow for males, but I can't figure it out? Does anyone know how to tell the difference??

 

[9tails]

If you can't tell the difference, the chances are that all your mollies are the same sex. There is a distinct difference between the anal fin which is located under their belly. Females have rounded fins where males have a gonopodium, a thin swordlike fin which they swing forward when mating with the female.

 

[dwayne]

Hey there! I just posted in your "fish aggression" thread... but here's the picture again to help you figure out the sex:

Top red line points to a female's underside fin, the bottom red line is pointing to a male's gonopodium (sp? reproductive organ). Excellent description, 9tails!

Good luck!

~Tara

 

[pisces11]

It's a.....Girl!

Thanks to your helpful advice I have been able to determine the gendre of my mollies- they seem to be all female, which doesn't explain their aggressive behaviour towards one another!!!