Hello, I'm fairly new here, was lurking and learning close to 20 years ago (!!!) and at that time had 4 aquariums thriving (20G/36G/10G/72G turtle). Recently have rediscovered my love of it and have been cycling a 55G (fishless), ready to stock in the next few weeks. I would like to have a school of 8 Congo Tetras, 10 Ember Tetras, and 15 Black Neon Tetras. I live in a somewhat remote area, and so will have to plan and order the fish ahead of time... when I called my not so local LFS, they said they can order Congos at a size of med/large/extra large, but no actual size/inch specification. Could anyone advise on what those vague size descriptions might mean as far as sexing? I would like to keep 5 males and 3 females. From what I've read on the internet it seems like this species is quite peaceful when it comes to male numbers within a group. It's a 2 hour drive to the fish store, so if I can get the F/M ratio I am looking for of the bat, based on "med/large/ex large" from LFS ordering would save me and fish a bit of hassle. 
TIA
TIA
