DWARF NEON RAINBOW (Melanotaenia praecox)

Very peaceful and suitable for many community aquaria given its relatively small size. Good tankmates include other similarly-sized rainbowfish, characins, danios, barbs, dwarf cichlids, freshwater gobies, and catfish such as Corydoras. Like other rainbowfish it can be quite skittish and does far better when kept in a shoal of at least 6-8, preferably more. The males will also be encouraged to display their best colours in the company of conspecifics.

https://www.seriouslyfish.com/species/melanotaenia-praecox/