Dwarf Neon Rainbowfish – A Complete Care Guide

Thank you for visiting! By the way… any links on this page that lead to products on Amazon and other stores/partners are affiliate links Aquarium Store Depot earns a commission if you make a purchase.

If you’re looking to grace your aquariums with a fish that is; easy to keep, active and beautiful swimmer, showcase bright, vivid colors that are eye candy, and loves the company of other fish, you should definitely look into dwarf neon rainbowfish.

Dwarf neon rainbowfish is an almond-shaped fish with an iridescent blue sheen that flashes under the light. Otherwise easy to keep, this fish is not for beginners, and in this article, I’ll tell you why. Not just that, I’ll also discuss everything related to the Dwarf neon rainbowfish.

Let’s get started.

Key Takeaways

  • Dwarf Rainbowfish live for 4 years and are schooling fish
  • They grow up to 2.5 inches and require a 20 gallon tank
  • They will not bother plants and most inverts in aquascape environments

A Quick Overview

Scientific NameMelanotaenia praecox
Common NamesDiamond rainbowfish, neon rainbowfish, Praecox rainbowfish, dwarf neon rainbowfish, peacock rainbowfish, and Teczanka neonowa
OriginNew Guinea, Indonesia
Care LevelEasy
ActivityVery active
Lifespan4 years
TemperamentPeaceful and compatible with community tanks
Tank LevelTop to Middle Dweller
Minimum Tank Size20 Gallons
Temperature Range72° to 82 F
Water Hardness8 to 12 dKH
pH Range6.8 – 7.5
Filtration/Water FlowModerate
Water TypeFreshwater
BreedingEgg layer
Difficulty to BreedEasy
CompatibilityCommunity tanks
OK, for Planted Tanks?Yes

What Is It?

Neon Dwarf rainbowfish, melanotaenia praecox, is a small freshwater fish species reaching a small size of around 2.5 inches in length. In the freshwater fishkeeping trade, it’s a popular fish that are an inexpensive yet wonderful addition to your aquariums. Dwarf neon rainbowfish are a schooling fish, perfect for a community tank with other fish of similar size and characteristics.

Origin and Habitat

In 1922, the dwarf neon rainbowfish, melanotaenia praecox, was first described by Weber and Beaufort. However, it first came to light in 1992. Neon rainbowfish is a beautiful fish found in small jungle streams in Western New Guinea (Irian Jaya) and the Mamberamo river of West Papua.

It is a schooling fish that prefers living in community tanks. Nowadays, the rainbow fish is raised in captivity, and research suggests it was listed as rare species in the wild in 1994.


The dwarf neon rainbowfish showcases the same characteristics as other members of the rainbow fish family. However, they are much smaller in size. Neon Rainbowfish, melanotaenia praecox can only reach up to 2.5 to 3 inches in length. 

The body of neon rainbowfish is long and it deepens with age. The adult male fish develop pinched faces with bigger eyes and twin dorsal fins than their cousins.

The neon rainbowfish have bright fins where the male fins are predominantly red and the females’ fins are yellow. The base of the body is usually greyish pink where the scales usually light up forming a bright blue (lavender to teal) color, depending on the light.

The overall appearance of dwarf neon rainbowfish is dazzling and allows for a beautiful fishkeeping experience. 


Neon rainbowfish are the smallest in the rainbow fish family reaching not more than 2.5 inches in length. The maximum size of the fish is around 3 inches in length in some cases.


The lifespan of neon rainbowfish is around 4 years. However, under optimum conditions, they can live for up to three to five years in captivity.

Care Guide

The neon rainbowfish is very hardy and easy to care for, but it is still not recommended for novice aquarists. The reason is they are very sensitive to water parameters and water changes. Despite their small size, they still require a decent-sized tank dedicated to around a group of 10 or more fish. 

I recommend keeping dwarf neon rainbowfish in a 20-gallon tank that is at least 20 inches long. Also, since these fish are omnivores, they will accept almost everything offered to them. However, the food at the bottom of the tank remains untouched. Therefore, I always advise removing the food from the bottom to avoid tank contamination.

They also remain healthy provided the water in their tank is kept clean and the tank conditions are hygienic. Thus, a good filtration system with good water movement is essential.

Aquarium Setup

Rainbowfish Neon are fast-swimming fish. Therefore, a longer aquarium is recommended to keep them swimming freely. Also, I recommend covering the tank securely. as they are active jumpers.

The aquarium plants should be added since these fish species look the best with floating plants, fine leaved plants, and these live plants also mimic their natural habitat and block the line of sight, especially when the males are aggressive with each other.

Tank Size (Minimum Tank Size)

Neon dwarf rainbowfish are fast swimmers and thrive in a community aquariums. Therefore, we recommend at least a 20-gallon tank. A 20-gallon long could be a good option for extra swimming space.

Tank Parameters

As mentioned earlier, neon dwarf rainbowfish are sensitive to water conditions. Therefore, the water parameters should be carefully monitored and maintained.

They are specifically vulnerable to pH levels and prefer slightly acidic water with a pH range of around 6.8 to 7.5. In a breeding tank, the pH levels should be kept lower.

The water hardness should be between 8 to 12 dKH and the ideal temperature is around 72 to 82° F.

The strict water requirements are the only reason I don’t recommend neon rainbowfish to beginners because they need more stable water than other school fish and they are larger.

Besides keeping water conditions optimal, you also need to observe water hygiene, the water should be very clean. Thus, I recommend doing 30% weekly water changes to keep your fish healthy and increase their life expectancy. Using a gravel siphon will reduce half of your time while doing water changes.

Filtration and Aeration

Before introducing the fish into your tank, check the levels of ammonia, nitrates, and nitrites to prevent the transfer of diseases and harmful toxins to your fish.

Investing in a good filter and air pump is necessary for your Dwarf neon rainbowfish tank. These fish species appreciate a highly aerated and oxygenated tank because they are very active and fast swimmers.

Since their tank requires dense vegetation, the amount of waste produced by fish and live plants should be cleaned proactively. The fish with high ammonia levels will eventually die. Therefore, to prevent this, I recommend installing internal or external power filters in the neon rainbowfish tank. The reason I recommend these filters is because they not only clean the tank but also generate current that your fish enjoys.

Editor's Choice
Hagen AquaClear

The Best Aquarium Power Filter

The worlds best selling and most reliable power filter on the market. Unchanged for years because it's so reliable and versatile

Buy On Amazon Click For Best Price

Besides installing an aquarium, aim to change 25% of the water every week to keep water parameters in control.


For the aquarium lights, you need to carefully choose your options. Neon rainbowfish prefer darker environments. However, since their tank is densely vegetated, you can provide low, subdued light.

The low light will also help prevent the overpopulation of algae in the water tank.

Aquatic Plants and Decorations

The native rivers of neon rainbowfish have a lot of plants to swim through and use as hiding spots if they are bullied by the larger, aggressive fish.

Therefore, always aim for densely planted aquariums to provide your fish with sufficient cover in the form of tall plants. However, while filling your tank with tall and floating plants, make sure they have a lot of free swimming places available, especially in the middle of the tank.


Choosing substrate is the most important and fun part of keeping the neon rainbowfish. 

Since Praecox rainbowfish are colorful fish, I suggest a dark substrate backing on the tank that contrasts with colors that make them look gorgeous and secure simultaneously.

Thus, a sandy, dark substrate with a densely vegetated tank and driftwood would do just fine for your Neon rainbowfish.

Community Tank Mates 

Neon rainbowfish loves a community aquarium with lots of aquarium plants. They get along with similar-sized, peaceful fish. However, avoid keeping them with large fish showing aggressive behaviors.

Another fun but important factor in keeping these fish happy in large schools is the ratio of males to females. Many aquarists keep the same sexes in the tank. However, adding both genders add more diversity and colors to your home aquarium. 

I know proper stocking of the fish can be daunting. Thus, here’s a little guide to help you choose the type of school you want to keep and the amount of fish.

Amount of fish to keep in a community tank

  • 5 rainbowfish – Do not mix sexes
  • 6 rainbowfish – 3 males + 3 females
  • 7 rainbowfish – 3 males + 4 females
  • 8 rainbowfish – 3 males + 5 females
  • 9 rainbowfish – 4 males + 5 females
  • 10 rainbowfish – 5 males + 5 females

The neon rainbowfish remains happy in a group of 10 fish or more. But please be informed there should be multiple females available for the males so they don’t stress them out. 

I also advise adding some bottom feeders in the tank as scavengers because your neon rainbowfish never eats at the bottom.

The ideal tank mates for Neon rainbowfish are:

  1. Tetras
  2. Platys
  3. Guppies
  4. Gouramis
  5. Barbs
  6. Other species of rainbow fish


Breeding Neon rainbowfish is fairly an easy task as compared to other freshwater fish. However, they are egg scatterers and so no parental care whatsoever.

Therefore, setting up a separate breeding tank is essential.

Once you have both sexes available in the appropriate ratio, they spawn every day. However, their eggs are just 1mm which produces a very small fry that is hard to raise.

Requirements for a separate breeding tank

Cleanliness and tank hygiene should be your utmost priority for the breeding tank as these fish are highly sensitive to water conditions. Here is a video by TM Aquatics below that goes over breeding.

I also recommend placing a floating spawning mop so that the adult fish can lay their eggs on it. Also, It’s advisable to place a catch-up because hanging a catch cup on the inside of the tank keeps the water warm and you can keep the spawning mop inside the catch cup with an air stone to keep the water oxygenated.

If you want to prevent fungal growth in the tank, you can add cherry shrimps in the tank to help clean the eggs.

The eggs of dwarf neon rainbowfish hatch in around one week. The newly hatched fry should be fed 3 to 5 times a day with infusoria or vinegar eels, or commercially prepared fry food. After a few days, the fry is large enough to feed on live foods such as baby brine shrimp.

To keep the breeding tank clean, I suggest setting up a sponge filter and fine-leaved plants or a spawning mop.

Keep these points in mind while breeding neon rainbowfish:

  1. The water temperature of the breeding tank should be set at 78.8 degrees Fahrenheit.
  2. The ideal pH range of the breeding tank is around 7.0
  3. When your fish are ready to spawn, they shine with vivid colors
  4. Observe the adult fish as they are egg scatterers

Food and Diet

Neon rainbowfish are omnivores and eat both animal and plant matter. However, in captivity, they should be well fed with high-quality flake or pellet food to maintain good health. 

You should also feed them live food such as brine shrimp, bloodworms, and tubifex worms. You can also feed them with blanched lettuce, leaves, or plant-based food from time to time.

How often should you feed them?

You should feed them multiple times a day but only if they can consume it within a minute.

Common Health Problems

Neon rainbowfish are very hardy and any disease in a well-maintained aquarium is highly unlikely. However, there’s no guarantee when it comes to life.

Always remember anything you add to your aquarium can bring diseases to your fish. Thus, before adding plants, substrate, decorations, and other fish, monitor them properly.

The best thing about Neon rainbowfish is their ability to fight disease. Thus, if you diagnose any disease earlier, there are high chances that your fish will recover from it.

Here are some common fish diseases: 

  1. White spot disease
  2. Velvet
  3. Fungal Infections

Differences Between Male and Female

It’s very easy to distinguish between a male and female rainbow fish. Look out for the fins, if the fins have a red outline, the fish is male. If the fins are yellow or orange outline, you’ve got the female. Females usually show a more silvery color than males.


How big do they get?

Neon rainbowfish are very small species growing for around 2.5 to 3 inches in length.

How many should be kept together?

Since neon rainbow fish are schooling fish, a group of 10 fish or more is recommended in a community tank.

Where are dwarf kind from?

The dwarf neon rainbowfish come from small jungle streams in Western New Guinea (Irian Jaya) and the Mamberamo river of West Papua.

How long do praecox kind live?

Neon rainbows (praecox) live for around 4 years. However, if the proper tank conditions are met, they can live for up to five years or longer.

What fish can live with them?

Rainbowfish get along with similar-sized, peaceful fish. However, avoid keeping them with large fish showing aggressive behaviors. They do best in community tanks with other schooling fish or other rainbowfish.

Final Thoughts

Neon rainbowfish are very active, beautiful, and hardy fish. They showcase striking colors that add opulence to your home aquariums. The best part about these fish is they live in harmony in a group of around 10 fish with lots of plants and free swimming space.

However, they are vulnerable to poor water conditions and may even die due to frequent water parameter changes.

Have you kept neon rainbows before? If so, share your experiences in the comments below!

Leave a Comment


9 Types Of Geophagus (With Pictures)
Cichlids are some of the most popular freshwater fish families in the aquarium trade, famous for their bold markings and colors, interesting behavior, and vibrant personalities. While many species have a reputation for aggression, one group of cichlids, the 'earth eaters' are known for their relatively peaceful temperament and amazing colors.
The 7 Best Plants For Cichlid Tank (That They Won't Eat)
Cichlids are aggressive towards each other, but are they aggressive to live plants? Most Central and South American cichlids can be kept with a variety of aquarium plants, but African species are more challenging to pair due to water parameters. It's not impossible though!
Why Angelfish And Guppies Are A Deadly Combo
You might think that guppies are easy fish that can be kept with nearly any other species, right? While these small, hardy fish can get along with most fish species, they are not compatible with angelfish. Keep in mind that angelfish are a type of cichlid, and so they should be treated as such.