Your photo isn't an orange flash. That's a domestic red. They're a way prettier fish than the orange morph.
I disagree with
@anewbie's analysis, but we've hashed that out unsuccessfully before. Females will claim territories, as will males. I have had males participate in broodcare before, many times. I've watched hundreds of first generation from wild caughts and domestic reds being raised by their parents. They breed easily and I would reckon about 80% of the pairs I kept bred successfully, and often successively. My sample was probably 20 plus pairs over 10 years. My cacatuoides have paired, for the period of egg and larvae defence, and into the broodcare phase. After that, they're done.
I recently bought a very young pair of supposed double reds, to have another look. I only have the two though, and they're still immature.
If you buy three and get sleeper males (late bloomers), they'll be killed. If the tank is too small, the slowest breeding female is done for. If it's a 4 foot tank, you're fine.
The tank belongs to your male now. To safely add 3 fish, I would steal a trick from the mbuna crowd. Net that male out and completely change the scape/decor. Move every rock and every piece of wood. Plants can stay where they are, but moving them wouldn't hurt. Do this while quarantining the new ones, so that you add all 4 fish at the same time.. That way, boundaries are broken (Apistos are visual creatures) and everyone starts with a chance.
Don't be surprised if 2 of the 3 new fish, or the older male, die in the sorting out of space.
@gwand just posted. Platys are not good dithers because they aren't fast enough. They also have a dangerous colour. Weirdly, I had blue wild X. variatus unbothered in a cacatuoides red tank once, but they weren't the colour of a rival male's fins.
