Okay so, my original plans for my 40 gallon breeder (36X18X16) got a bit derailed by the fact that even the 3 petsmarts and 5 petcos around me (plus the specialty store I use) don't carry the types of tetras I wanted to put in my tank. So right now it's looking like I'll have 5-6 (male) mollies, and 5-6 (male) guppies, alongside my 6 bronze cories (3 albino, 3 regular). Thing is... I feel like the tank will look a bit empty with just 16 fairly small fish (63% stocked according to Aqadvisor), especially since they don't really school (Oh the corys hang out when they're resting, but they really just like to explore the tank individually I've noticed, so it takes away from some of their appearance.) I've currently only got 4 of my cories (my starting fish) and 3 mollys (they need to finish quarantine so I can go get the other 2-3 since I don't plan on adding too many at any given time). So, the question is... What else CAN I put in there? Or should I put in there as things may be... The tank's fairly warm (74-76 ish on both thermometers), well planted, with 2 driftwood (1 real, 1 fake), and a large cave, no ammonia, no dirt, I vacuum the gravel every week, and there's a smooth gravel mixture on the bottom. I'm looking for something to be a real flash in the tank; common enough to be easy to find in one of my 3 pet store options, but uncommon enough (or pretty enough) to really catch the eye at just a glance to the tank, and not dangerous to my other fish.

Anyone have ideas?