Sometimes these immediate pairings work out okay but sometimes they go sideways. The “newness” wears off and the pairs realize they aren’t compatible, usually after a disagreement over the care of the eggs or fry, and one of the fish ends up shredded. If you are isolating them with no dithers at all, make sure you have plenty of cover and hiding spots in case one needs to get away.
Agree.
What I don't completely agree with is the earlier comment that it's common for cichlids to pair up immediately-- and I have decades of experience. That may be true of some species, but not all. Some species can be picky about pairing, including Heros species. It's a mistake to think you can put any two of any new world cichlid species together and expect a compatible pair. In some species they're just as likely to kill each other, in some you may have to take your time introducing them, starting with a divider. In some species how it goes will totally depend on the individual fish-- getting an instant pair with these
can happen but there's no guarantee. Heros (severums) are like this, some acara, some geos, and some other species can be like this. Some will pair quickly, some will pair after a period of time, some will pair and spawn a time or two, even produce fry, then lose interest, or the bond may wax and wane. In some cases I've had Heros pair basically ignore each other in a cichlid or Heros community after a brief or loose pairing (these were types where male and female were easy to distinguish by facial markings), while some will fight afterward. I've had all of the above happen with severums.
Right now I have four A. metae. A day after I got them they split into pairs, one pair bonded closely and has mostly stayed that way, the other not so much. For a while I had two pair defending territories at opposite ends of the tank. The second pair bonded briefly, cooperated closely in defending their end of the tank, then waxed and waned for a while until the male lost interest. He's not aggressive to his former female, mostly just ignores her.
You can't extrapolate pairing and breeding rules for all SA cichlid species, or for individual pairs, from experience with some of them.