The Weald Aquatics Blog - Neon Blue Rainbow or Neon Dwarf Rainbow (Melanotaenia Praecox) - another blog post from Weald Aquatics | Aquarium & Pond Fish Shop in Kent


Coolings Green & Pleasant
Main Road, Knockholt, Kent TN14 7LJ

01959 532 963

Opening times

Monday to Saturday
and Public Holidays: 09:00 - 16:00
Sunday: 10:00 - 16:00

As a pet shop, we are exempt from the government's ban on shop closures. So we cautiously welcome you if you need any supplies during this time. However, whilst in the shop please observe the rules on social distancing in order to keep yourselves, other people and our team safe and well.
Site Menu

Neon Blue Rainbow or Neon Dwarf Rainbow (Melanotaenia Praecox)

Blog post written by Andy | 19 July 2011 | Category: Tropical fish

I had a really great response from people on my last post about the Boesmani Rainbow (thanks for that!). So much so that I thought I would do another one sooner rather than later!

Lots of people have been asking me if there is a rainbow fish which doesn't grow so large and is therefore better suited to the smaller aquarium...and wouldn't you know it, there is!

The Neon Blue Rainbow or Neon Dwarf Rainbow (Melanotaenia Praecox) is a great rainbow fish and as the name suggests it stays small. It originates from Papa New Guinea and Irian Jaya where it is found in the lush jungle streams throughout the area.

They share the typical rainbow fish shape but on a much smaller scale. Adults rarely exceed 2" with females slightly smaller, they have the characteristic arched back, twin dorsal fins and large eyes. The males are a metallic neon blue colour and as they twist and turn in the light they do seem to glow. They have deep red fins and a bright red tail. The females are slightly smaller and do not develop such a deep body, they still have bright reflective blue scales but this time they have bright yellow fins and a golden yellow tail.



As with all rainbow fish they prefer to be kept in a small shoal, I find at least four but the more you have the better. To truly get the best colours and behaviour from these fish it's best to keep them with a few females for them to show off to - try having more females to males if possible. When you have a couple of males "dancing" to get the attention of a female, it's difficult to look at anything else in your fish tank!

They naturally live in densely planted streams so provide plenty of plants to give cover, providing floating plants also replicates their natural environment. Try and provide some areas of open swimming space for them to cruise around as well.

They are omnivorous so benefit from a mixture of prepared and frozen food, giving them live food regularly also keeps them in top condition and keeps their colours strong.

The rivers they are found in have quite strong currents so a good filter or air pump to keep the water moving and well oxygenated also helps them feel at home. They are not a demanding fish so a regular water change of between 20-25% should be ample to keep the water quality up and these fish happy. Try keeping them with similar sized tank mates, too many large fish may intimidate this smaller species and cause them to lurk in plants and hide at the back of the aquarium. It's great them looking good in our shop but if they hide in your aquarium you will be disappointed! The Praecox Rainbow is a beautiful little fish that if kept happy makes a fantastic show fish for the smaller aquarium and one I happily recommend.