What size tank would i need for...

[Jawz]

a green terror, a jack dempsey, 1 firemouth, one or two convicts, and maybe a oscar?

180 gallon? or more?

 

[Brobro]

a 180 would probably work, but im not the cichlid master, so i would get another opinion too.

 

[fishboy]

I'd go for a 200 myself if you have the extra cash.
Daniel

 

[Doomhed]

i would go 250 (not that much more, only like $150 more) and add a ghost knife or 2.