Meh, my rummynose can go pretty nuts over floating flake. They're such voracious eaters, they bite EVERYTHING that comes in the tank. Snails, droppers, my fingers if I keep them in long enough. Tetras have appetites.
My Golden Rule of planted tanks: WWTAD-
"What would Takashi Amano do?"
Piranhas get too big for my taste. Especially for this sized tank since I usually like keeping larger schools. I've kept some red bellies before and they became rather boring after they got bigger. They just became lazy and didn't swim as much as they did when they were smaller.