Firemouth, Portalgrensis, Aquidens pulcher, or any of the Acaras, Gynmogeophagus balzanii, Geophagus altifrons ("surinamensis"), Rainbow, Festivum, Salvini, Blue-eyed cichlid, Emerald cichlid, Cupid cichlid, you COULD technically do a female Green Terror but certainly not a male or pair, but I know/known people who have accumulated various females scattered around their fish rooms in the search for a male, they did just fine in smaller tanks. She CAN get 8", but i think you'll find 5-6" is the most common LARGER size you will find most female GTs. You could very well end up with one that stops growing at 4", i sure have. There's to name a few SA/CA, however there are also
Krobia xinguenses.
Wow those are awesome I've never seen them though.
if you go by MAX size then possibly, so 7" would be absolute largest, however, the vast majority or ANY animal usually hits the "average size" and growth slows considerably. Like the female GT, there is a good chance your Salvinis will only reach 4"-6". I thought similarly of the Balzanii @ 10" and was told by "The Guys" here that is very unlikely, most only reach 4"-8", and 6" is most common. As with Convicts as well, females SUPPOSEDLY hit 4", but I never had one grow over 3" and I bred and raised a LOT.....no really, ALOT of Convicts.....most common sie is 2.5" - 3", again the average is likely what people will end up with.Wouldn't salvini or blue acara get too large? I already have a male GT in my living room display looking for something a little different. Firemouth are also interesting but I don't know if I would only end up being able to keep one in that size tank. I imagine two FM may kill each other.
a 10" FM????!!!!! WHAT? that's insanityI've had FMs reach 10", that tank would only be a grow for them (although it takes a while), I would also think its too small for most Geos, a couple small Gymnos maybe.