Though I probably wouldnt have been quite as harsh as japes, ive agreed with everything he has said so far.
age is no excuse, i started joining forums when i was 12 (now 16)
so, if you are new to the whole fish thing and still learning (as all of us are really), why not listen to someone more experienced then yourself? i can't really say i see your stance on the visual learner aspect of this, if someone tells you a fish is going to kill the other, do you really have to test it? or even better, take the warning and go do a bunch of research, that way you have really learned it. It was inevitable that one of your Centrals was to kill the S. Leucosticta, anyone who has done research would know this.
You need to understand japes side of this, most people on this forum have high respect for the fish they keep, and cares about the all fish in general, therefore seeing someone buy 2 very incompatible fish, in this case when one was bound to kill the other, is not something people on here, including myself, take lightly.
All we are trying to do is save the fishes life, because it was going to be killed.
With the "sometimes it works sometimes it doesn't" attitude in this hobby, you will not make it very far, sure, you may have some, normally incompatible, fish together, but how many lives were sacrificed to get there? Usually, there were more then just a few, or you may have just gotten lucky, regardless, most of the time fish don't work this way.
Now just to add, I went through the stage of this sort of impulse buying a long time ago, and I 100% understand where your coming from, but thing is, once the stage wheres off, you will realize just how dumb it was, doing what was done to the fish.