How long have you had them? Rams don't live too long, 2 years is a long time for them. Also, if you haven't had them that long, do you know what the sexes of each of them are? If you have more than one male, it can be hard to keep one from eventually killing the other. Also, I am not very aware of a difference between german rams and blue rams, for I have always seen them labeled, and talked of them, as german blue rams, so who knows!
Tank in transition! 55 gallons, hard water.