I got some platies at my local Petsmart that were labeled "Sunburst" and they're pretty colorful. They're bright orange in the center, getting darker orange toward the extremities, with black tipped fins. As you probably already know, platies are hardy and don't grow much more than 2".
Of course, I also love neon tetras. I don't care if they're the most common tropical community fish, I still think they look awesome. Blue, red, flashes of silver-blue, they're just beautiful. With a 120g tank you could have a lot of them. Sometimes I think I'd like to have a big tank full of them, maybe 50 or so

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