So you've decided to buy a pair of these gems... maybe in the hopes of breeding ... but even then ...they are lovely to keep as a couple as a male & female... even if they don't breed they will happily live alongside each other and stay together pretty much all of the time. We all know how things can be if you put two females or two males in a room after a while <grins> That is not to say that these characteristic little guys never have a 'lovers' tiff - mine often get the hump with each other but usually make up again pretty quickly.
So your in the store and you see a tank full of these cuties... usually if you can get comfy and the store owner is not bothering you too much you can watch their behavior and pick out a dominant male pretty quickly - even when they are young... a dominant male likes his ladies and will have picked his favorite in the tank... by observation and patience you should be able to see 2 rams that have taken a shine to each other as they will stay together quite a lot... usually this is already a good sign that it is a male and female... but you have doubts niggling in your head so to be sure here are some signs.
Will have black stripes going though her pelvic fins (this is a great one to remember as when they are very young this coloring already shows if all others fail... the stripes are usually also apparent in a stressed colorless fish)
If she is a happy little gal and shining then you can see that her shiny blue dot's cover her side black marking.
If she is a very happy little gal then her belly will show a pink hue to let those men know that she is ready for a mate.
Sorry for the horrible pic of her.. (she'll kill me if she see's this on the net) but it shows nicely all the above points
No black lines in the pelvic fins
The black marking on the side is solid black
Bigger built and the dorsal fin will be longer and spikier
Not a pink hue in sight on the stomach area
I hope this helps some peeps who are going to treat themselves to a pair of these beauties or those who have some doubts on the ones they have.