Before this gets closed, let me add this.
Unless these fish are only sold with permits validating ownership, then you will always have people trying to see something get ripped apart.
It's the nature of the reputation they have as fish.Although they are some of the most skittish fish in Amazonian existence.
If an Amphilophus was properly equipped with the same teeth and even ran in the same numbers, the P's would be really low on the aggro scale.
Ever see a P mess with you at the glass like an RD would?
They are just novelty feeds. I.e interesting to watch eating.
So as above stated, unless you treat P's like guns, and record all of the owners information, and maybe even a mandatory owners course, then keep expecting this immature low self-esteem crap.
Because last time I checked the Rio's and their tributaries, there are NO Koi in CA or SA!