What To Put In A 40 Gallon Community Tank?

[brodysfish]

I am getting a new 40 gallon tank and have had a hard time trying to decide what to put in it. I think I want to have a south american themed tank with some cichlids in it. I am also thinking of having miscellanious fish such as elephant nose, black ghost knives, hatchetfish etc. Could anyone give a suggestion on what fish would go for either of the tank ideas??? It would really help me a lot in saving money and not having to change things throughout the process.

 

[fluttermoth]

Could you post the dimensions of the tank and whether your water is hard or soft, please?
 
It would be irresponsible of us to recommend fish species without knowing those.
 
I can tell you that both elephant noses and BGK need a much larger tank than a 40g, and neither are suitable for community set ups.