When do Butterfly Goodeids sex out

[Nordlys Fish Room]

This is my first time with splitfins/goodeids.  I bought (5) fry in august last year. They’re currently about 2 inches long and roughly 6-7 months old. So far they all look female still and obviously I was hoping for at least one male. I was wondering if someone more experienced could give me an estimate on when they start to sex out. 
 

Tank stays about 68-70 degrees Fahrenheit in the winter. 

[shkote]

At 6-7 months old, the andropodium should already be visible on males. Mine are usually sexable around the 4 month mark. I do sometimes have males that take a little longer to color up, but the andropodium is still evident on those males. 

[Nordlys Fish Room]

5 hours ago, Lynze said:

At 6-7 months old, the andropodium should already be visible on males. Mine are usually sexable around the 4 month mark. I do sometimes have males that take a little longer to color up, but the andropodium is still evident on those males. 

Thanks. It looks like I’ll need to get a second batch this spring if I want babies.