I used to have 10 rummynose tetra... they are pretty hardy
I just found that you wld still need to have the right temp, water parameters and group them with the right tank size and environment. They love to have room to swim (long tanks). with small tanks, expect suicide jumping.
I would say that Rummy Nose Tetras are quite hardy, and a pretty good beginner fish as long as they have the right tank size, which I would say is 25 +gallons. They are fairly active fish and that’s why they need a decently sized tank.