Females will be plumper when laden with eggs whether or not they have fed, but males stay pretty much thin all the time unless your overzealous with your feeding habits.(which you should not do)
Looking at the front of the males will see their stomachs looking hollow just before your to feed them.
Females at this time will still look plump or fat in the belly region.
To breed them I suggest a group of 6-8 with 3 males and rest females. I use to put them into a preset-up 20 long the night before breeding was expected to commence then the following morning they would breed with first light coming in through the window of the room(do not feed the parents in the breeding tank)
No gravel in the breeding tank, but either lots of moss across the bottom or double layer of marbles works to keep the eggs out of reach, or if your really trying to keep every single egg to hatch out(multiple times) and raise up to adulthood use some mesh screen siliconed to one long side of the tank(the back, all the way across tank from end to end) and "U" shaped down and up to the front of the tank leaving half the tank volume under the "U" for the eggs to fall into. The mesh size should be 3/16"-1/4" hole size like some of these:
http://www.industrialnetting.com/plastic_oriented.htm, or similar, bought at a store locally for you like Home Depot or other.
Put the front edge of the mesh over the front of tank with the glass cover on top to hold it into place. Then when the parents are finished breeding remove them and fold the mesh over the back of tank out of the way until you do it again.
Temp around 76-78 and preset-up sponge filter and use Infusoria or microworms for first foods of young, until they look big enough to eat pulverized or powdered fish food, then adult food 3 weeks later.
