Conditioning the fish usually requires extra food and higher protein foods. You need to look at the protein contents of the foods you are feeding. ( read the label
) Compare that to a frozen ( not freeze dried but actual frozen) black worms or tubifex worms. Worms are what I have always used for conditioning because they are high protein foods. If you are currently matching that level of protein intake for the fish, you need to up the feedings then because the fish may not be getting enough food to produce the eggs. There is much debate over force starving your fish and personally, I see no actual reason for doing it. A good quality diet will not require you to starve your fish. Wild fish may not eat every day however, your fish most likely are not wild fish. They are tank bred which means they were used to being fed 3-6 times per day, every day, to get them large enough to get to market quickly. Now, you have reversed that and are barely feeding them ( I assume) and starving them for one day. Breeding fish is not the same as keeping them in a tank. It's a whole other animal. So I suggest at least 3 feeding per day containing both high protein foods and flake that has vegetable matter (so that the fish does not get backed up) or frozen brine shrimp that has not been fortified with extra protein. The chiton in the body of the brine shrimp is roughage and good for making the fish have normal eliminations.
(FYI: Wild fish get all that protein and roughage in their diet naturally so unless you are feeding your fish the exact same thing as wild fish are eating, you shouldn't follow wild fish recommendations. (IMO) )
So start with that.