This is a rainbowfish, the previous scientific name was Popondetta furcatus but it is now validly known as Pseudomugil furcatus.
It must be kept in a group, minimum 6, so you are good there. It prefers basic water (pH in the 7's) and some hardness (15-30 dGH).
Being small, it needs suitable quiet tankmates. The rams will probably leave them alone. Killifish may or may not, depending upon which species you have. Dwarf gourami can be questionable, as they prefer the upper water level and these rainbows are surface fish. Lots of floating plants will help.