Aplochielichthys normani/Poropanchax normani (new nomaclature) are quite readily available these days. They are a shoaling species and very small, they like a good water flow and they love swimming against this. I would suggest that you buy a dozen or more. They are not too difficult to sex.
They like clean fast flowing water water with a pH of around 7.4, General Hardness should be around 120ppm and temperature around 78'F.
Aply.Porop. normani males have more pointed (yellowish) finnage than the females whose will be more rounded, also the males will have a slight blue tinge to their abdomens whereas the females body will be silver. The females will be slightly more robust and rounded in the belly region also, with good feeding
Like most killifish they do not like bright lighting, so a densely planted tank, dark substrate and surface plants will show them off to their best advantage.
The fish like to spawn in crevices and if you would like further info on breeding then just ask. They will take to flake and frozen foods readily and the adults love newly hatched brineshrimp and Grindalworm.
Hope this was of some help
Regards
BigC