i still think cons may work. they have the speed of a good dither and are tough enough to work as a target as well, even with the big guns your stocking. but like i said i am unsure if adding another ballsy fish would be good for the dynamics of the tank. someone will chime in who has used them this way.
Yep I agree. Convicts are hard little b**tards, have used them in the past. A male female pairing could cause problems especially if there isn't enough tank floor space though. Got in pair in my current set up, which includes a Jag, RD and a Mayan, been in there now a couple of months no problems. Won't spawn though as they are way to busy defending territory. Cutters are another option, similar spec as a Con but a little less robust. The only fish that has destroyed my previous kept Cons was my old Channa snakehead but thats another story.....
SD I believe means Silver Dollar, Metynnis hypsauchen, can get up to 7" but need to be kept in a small school of not less than 4. Could be a better proposition if tank floor space is limited as they are mid to upper water swimmers.
Have a good tank setup, plenty of cover, plenty of seperate caves,etc
If you decide to go convicts I'd get all males. While all females could theoretically work I've heard of 2 females forming a pair with eggs laid (infertile of course), and having a mated pair can really cause problems.
I have 2 SDs and they get pretty big. Red hooks look a little neater but I don't think they get as big as SDs. Tinfoil brabs get too big IMO. with you guys, angels are way to slow to be kept with cichlids. Altums might have the size, but the answer is no.