Fish shown in the above pictures are part of the breeding colony.
 
Though they are small fish they still need a decent sized tank. This is because they do best in groups of 10 or more. It is advisable to keep these rainbow fish in a tank at least 60cm long and ideally 60 or more litres.
The Neon Rainbow will eat most anything offered. Neon Rainbows are classic omnivores, quite equally adapted to eating both animal and plant matter in the wild. In captivity they should be fed a high quality flake or pelleted food to maintain good health. Buy foods frequently and in small amounts, as the nutritional value of these products quickly deteriorates. Feed these fish several times a day and only what they can consume in under 5 minutes.
These rainbows will do best and are most effectively displayed in tanks which simulate their natural habitat. A sandy substrate, dense vegetation, and bog wood all echo the native rivers of the Neon Rainbow. As with most of the Rainbow species they are most at home in well planted aquariums. When you choose plants make sure to pick plant that can tolerate the hard, alkaline conditions preferred by this fish.
A rainbow tank can be quite spectacular with the proper technique. Although these adaptable fish would certainly be happy in most conditions, the colour is best displayed with a little planning. A dark substrate and backing on the tank contrasts with the colors and makes them more secure. 
The Neon Rainbow is basically adaptable to life in the community aquarium. They will get along best with other peaceful fish of a similar size. 
Neon Rainbows are schooling fish and the ratio of males to females is very important to keep a reasonable peace among them. Although you can always keep single sex schools, you will see significantly better colouration if both genders are in the tank.
Species – Melanotaenia praecox
Common Name – Neon Rainbow
Origin – Mamberamo region of West Papua New Guinea
Diet – Omnivorous
PH Range – 6.5 – 8
Temperature – Tropical and Coldwater 22°c – 26°c
Breed Type – Egg Scatterer
Grows to approximately 6.5cm