you already have a jag so maybe a wild caught pair of festae or a small-med community like sajicas, blue acara, severums, JD, tho.sp, gt, nics and plenty more.
a tho. sp species tank would look great, all the same sp tho
I am trying to do an all Aequidens tank. Like Diadema, Metae, Korias, Patricki ( even though not all that rare) and maybe a pulcher but I don't know yet. Possibly some key holes in the mix for smaller fish.
It seems everyone likes the Jag option but I am trying to stay clear of CA's as of now but I never had a Jag pair let alone a WC Jag pair. I was thinking Discus because in the past I loved to keep them but they weren't as personal as more aggressive fish. They wouldn't hide or anything it's just lacked feeling lol. Thats the reason for the Mbuna. Tons of attitude in a small package and pretty too lol. Plus you can pack the crap out of them and it is completely fine. Mbuna tanks are very attractive.
Polys are awesome and I would definately go for that but they are pretty expensive around here and I can't buy many of them as they aren't common.
The Aequidens idea sounds best to me, mostly b/c it's something most people don't keep. Personally, I like the smaller acaras (Krobia, Bujurquina, Laetacara) but as a whole I think acarasare very underappreciated these days.