Sexing GBR

[Sjscott2505]

Hi

I have just bought a new blue ram to add to my 180l tank. I already have 2 gold rams that I believe to be make and 1 blue ram that I am sure to be female. The 2 gold rams tend to chase her a bit, leading me to purchase a new blue ram that I was told is female to draw a bit of the two males attention.
I have had difficulty sexing them personally as they do not have obvious colours and arnt at a mature stage yet. I have posted a picture of each, please let help me sex them. I am concerned that the new addition is a male, likely adding more conflict to the tanks

 

[Colin_T]

Females get a pink belly.
Males have longer fins and the first 3 fin rays on the dorsal (top) fin are black and longer. Gonna be hard to tell the colour of the fin rays on the gold rams but look for a pink belly.