jonnythefishkeeper

i would say hatchet fish for the top
rummy nose or cardinals for the middle
corydoras for the bottom or giant whiptail catfish
if any room left i would get some golden panchax!

DVS Moss

1. Neon Tetra
2. Fancy Guppies
3. Sword Tails
4. Mollies
5. Corydoras

GrandePippo

My experience tells me there is NOTHING like the rummynose tetra. I think they are by far the best schooling fish out there. I had around 60 of them in a 500 liter planted tank and their behaviour was amazing. Great fish. Number one definitely for me.

Rasboras are also very good option. They also school nicely together and they also have very agitated behaviour. Seem to like current.

The pristella tatra is also a good schooling fish, but a little shy. I kept a shcool of around 12 of these in a 100 liter tank with lots of small leaved plants. The fish tends to be intimidated by the lights, but when the light is subdued they display their best self. Like the rasboras they enjoy current.

Only the above mentioned three species have displayed a close schooling behavior in my tanks.
My other experience is with blue neons, black neons, lemon tetras, glowlight tetras, penguin tetras, Paraguay tetras, and some others.

Good luck!

Tausendblatt

Odessa barb is a great schooling barb. It has the best color of any freshwater fish I have ever seen: black, blood red, green, yellow fins with black spots (like a kiwi with seeds in it almost) There is a blue sparkling spot behind their head.

They stick together really well and are fairly small, don't bother plants or anything. They swim faster than most fish, and seem to notice the owner, plus "beg" for food in a dance. I guess do that too, but they are so fast it's ridiculous.

The females are bronze with red fins, and the same blue spot behind their head.

marrow

ember tetras
Columbian tetras