It's a cichlid from the Rift Lakes I'm pretty certain but I'm no good with the names there are so many. I'm probably wrong but it might be some type of Zebra.
maybe they had a pair and didnt mention it.....or it was getting fruity with something else or the owner had great water conditions and a good camera....
Yes, that is definitely Hemichromis guttatus . When young my Male had colouration like that and I don't think it necessarily signifies breeding condition. That is a lovely one you have there all the same, they are exceptional hardy fish and once they get older they often develop more blue on their sides.