Are My Cichlids Trying To Breed?

[tonilee7]

Hi, I have 4 oscars which I have been trying to breed for a few months now but never have any success. I was beginning to wonder wether I had 4 females or 4 males. This morning I was sitting watching them and I noticed that every time 2 of them cross paths they quiver really quickly, but then the bigger oscar comes over and harrasses them. Could it be possible that these to are trying to breed but the bigger one is interupting them and also if anyone has any idea's as to how to tell males from females please don't hesitate to tell me as I have been told many ways but still can't tell the difference.

Any help will be much appreciated!!! toni