‘Neon Tetra’
I didn’t find these to be drastically different from other tetras. They’re smaller, and sexing is harder, but they were frequent morning spawners when isolated in their own 2.5 gallon tank with r/o water. I kept the tank blacked out (under a cardboard box) based on conventional wisdom but I don’t know for sure that that was necessary.
I suspect that a lot of tetras with a reputation for being difficult gained the reputation back before r/o water was easily available and breeders had to gather rainwater and/or filter their tapwater through peat and resort to other measures to get water soft enough for the eggs to fertilize.