I'm mostly worried about room for them to swim along the ground, up and down space is beyond fine for these guys.
They'll need other fish to break in the tank for them first, though. Hence Neons are my first thought because Neons are tiny and put up with almost anything. Main thing Neons need is other Neons, pretty much.
View attachment 154659
For reference on them.
Granted, most people who know about aquarium stuff probably know them from the name, but after the last time I mentioned them I remember not all people do.
You can even catch Neons in the Jungle biome in Terraria and sell them for cash. Fitting enough, considering they're native to the Amazon river basin IRL and someone basically went "hell these are pretty, I bet I could make money off of these."