Rainbow Emperor Tetras

[JJB]

I've kept many tetras in my day but have not kept these. Thinking of getting some for my 55 gal planted tank. For those who have kept these, any recommendations/pointers on minimum number to keep together and anything tricky about them? Also, could these be kept in a nano tank, something between 6 - 10 gallons? I didn't think they would be good for nano, but thought I would ask. 

[Fish Folk]

@JJB — this is not the answer you’re looking for, since I’ve no personal experience with these. However, you’re asking a good question, and I think it’s fun to learn. So here is how I go about it...

(1) fishbase.se is often my first stop. If a fish is well-known, usually there is good information about it there. https://www.fishbase.se/summary/Nematobrycon-lacortei.html
 

It appears that the common name for these tetras is “Rainbow Tetras.” I’m not seeing “Emperor” there — unless that’s an occasional title, or a different subspecies. Entering Nematobrycon lacortei finds the species. Owners upload their photos (see below). 
 

(2) Next, I go to YouTube, and enter “Rainbow Tetras”+Nematobrycon ... and here it becomes clear that the common name confusion is due to “Nematobrycon” broken into subspecies. “Rainbow Tetras” are, as stated above, Nematobrycon lacortei. But “Emperor Tetras” are Nematobrycon  palmeri. Before watching YouTube videos, I go back to fish base.se...

(3) There, searching up “Emperor Tetras,” I see more information. https://www.fishbase.se/Summary/SpeciesSummary.php?ID=10683&AT=Emperor tetras
 

First off, Emperor Tetras grow slightly larger than the Rainbow Tetras. Recommend tank size is “80 cm” which amounts to 3 ft. (See screen shot attached). So, I would infer that the best plan would be a school of 12 or more, minimum 20 gal. long aquarium. That’s not a “rule” but just an educated guess. Now back to YouTube...

(4) There seems to be more taxonomic confusion on YouTube... some hobbyists conflating “Royal Tetra” (Inpaichtys kerri) with “Emperor Tetra.” Here is one species profile...

Sounds like they’re fin-nippers, so take care with slow-moving, long-finned tank mates.