my poly are get along quite well with group of raphael catfish (A.K.A platydoras or humbed catfish) and also with my albino brushmouth pleco. they always swim together nor grouping in the corner of the tank.
(but maybe when poly gets to big, i'll remove the catfishes)
125 G
2 x 6" albino senegals
2 x 6" P. Endlicherii
1 x 4" brushmouth pleco
4 x 1" platydoras (raphael catfish)
after a year in captivity
note: size ratios does matter!!!