Cichlids aren't a fan of Hex tanks either, its a lose lose.
I... can never really think of anything that would be happy in a hex tank... I mean, i guess planted with some small tetra or something.
Unless this was a freebie, or you got it dirt cheap. Take it back and get a cichlid friendly tank.
I think the bare minimum you could happily house any small to medium sized CA/SA cichlid (not counting cons and Firemouths) would be a 55 gallon standard... Some might argue a 40g breeder due to its width might be better, but most of us agree, if you want anything in the 12-14" category (Average size of these types of fish) you'll want a 75g tank
lol, i hate hex tanks, nothing looks good in them i swear >.<
Maybe a climbing lizard like some type of Gecko, or a large abboreal (sp?) tarantula (Pink toe , nice and cheap) would appreciate the large tank with some nice live plants.