Puzzled! Are My Two New Young Kribensis Male Or Female?

[jacx14]

Good day!
 
Yesterday I purchased two new Kribensis from a local aquarium. They are quite young so the man in the shop couldn't say for sure what sex they were.
 
Please take a look. The first three pics are of the first, smaller, Kribensis. The last four pics are of the larger Kribensis, which I think is larger because of age and is from maybe a different, older, set of fry. Any ideas?

 

[jacx14]

Also, can anyone tell me at what age they become fertile?

 

[JonesyJ666]

both are female

 

[Lunar Jetman]

They do look like they are both females but the photos are not the clearest/straightest..

 

[jacx14]

Thanks very much guys