Pleco coexistence with agressives

I know from experience that a pleco will not coexist peacefully with my
buttikoferi, unless of course you consider the pleco becoming a midnight
snack a peacful coexistence.

suspect number 1: http://home.comcast.net/~polarhound/marty2.jpg

I'm wondering about how my Leporinus Fasciatus will react to one, and
wanted to see if anyone had any experience with them before I sacrifice
another. Looking at one for this tank as brown algae is starting to
move in... Although the algae DOES give the white gravel I had second
thoughts about after putting it in a bit softer look..

suspect number 2: http://home.comcast.net/~polarhound/leporinus1.jpg

At least I know one will exist with the tiger barbs I had to rescue out
of my father's tank.. (why he thoughts barbs and angels could live
together is beyond me)