These are Andinoacara coerleopunctatus (I expect close cousins), but you haven't stated which species acara you have, there are many.

Above is a female with fry.
Below the male (father of the fry).

You might notice the females seem to sport more dark markings during breeding season, males bodies tend to be slightly more elongated
The females dorsal, and anal fins reach about half the length into the caudal, the males reach longer, and can even surpass the caudal, below.

The males head profile is usually much more steep.

When not in spawning mode, the colors are less useful as a gender determiner.
Below a female not in spawning color, but the length of fins trailers remain significant traits.

Yours appear to be too young, for me to visually sex.