get a 180 and some dithers and those 3 should do alright. just need a large enough footprint where they can each have there own territory, and put in some visual breaks so they dont have to look at each other all day. (i currently have a community of 8 oscars, 6 red devils, 2 jags, 2 tinfoil barbs, 2 crenicichla sveni, 2 convicts, 1 red bay snook, 1 gt, 1 jd, 1 pacu, 1 clown knife, assorted cats and plecos.) so i know for a fact those fish should be compatable given enough of a footprint.