If there is just the pair in the tank, you just let nature take its course, a well bonded pair will fan the eggs, and care for the fry.
If there are other fish in the tank, unless you remove them, the pair will kill the others if they can.
If the not able to be killed, the others will eat the fry unless you remove them.
I often remove some of the fry to a breeder box, once they are hatched with a turkey baster.
If she's darkening, she's ready to breed.
The eggs take a few days to hatch, and the first few days after hatch, they don't need to eat, because they're using up their yolk sacks.
Once they become free swimming they will immediately need to start feeding.
I buy brine shrimp eggs, hatch then over 24 hours, and use newly hatched brine shrimp as a first food, and leave as much algae as possible on the tanks sides so they can constantly graze.
I also raise daphnia in my rain barrels as next food.

I remove all fry after the fry reach about an inch, or if the parents start cleaning a new spawning site. If they spawn again they will often eat the older fry.
Below is a breeder box, that can hang in the same tank with parents.

I use brine shrimp hatcheries I get from brineshrimpdirect.com, they come with eggs.
Although there are many DIY ways
