That's a German blue ram, Mikrogeophagus ramirezi.
To sex M/F, look for pink on the belly of the females.
Males have different 'spikes' also on their dorsal fin - the female's fin pretty much is straight across but on the male the third or fourth 'spike' is taller.
There's also a more subtle difference on the black/blue spot on the side...the male's is more solid and the female's has blue bleeding through the edges, as I recall.
Post pics of the other two and I or someone will try to help you sex them.