ah the guy is from taiwan. they love their plecos over there as much as anyone lol. i looked at the other videos, and i still think they look healthy. what he has done is gone for a big piece of bogwood and no hiding places, which will stop agression so much, which allows him to have so many plecos. there are a couple of non feeding vids and it doesnt look so hectic. but now i KNOW, i will agree there is just a large population tank in not a small tank, but a tank that is small for the amount of plecos. sometimes this will work. id be suprised if they all ended up dead though. if water quality is kept fine, they should be fine. they are probably fed a lot too, but hey thats speculation. not the way i would do things, but each to his own. he has some very good looking plecos in there, and a few expensive ones too