Yellow Rainbowfish, also known as Melanotaenia herbertaxelrodi, yellow rainbows, Axelrod’s Rainbowfish, or Lake Tebera Rainbowfish, is a fish that does not demand much care. Its scientific name was given in honor of the famous fish enthusiast that funded the expedition leading to its discovery in September 1980. Yellow rainbows are a friendly bunch that appreciates being with fellow fishes.

Although raising this yellow aquarium fish is relatively manageable than others, it is essential to be aware of its technicalities.

This article will provide information on the proper care, maintenance, and breeding of Yellow Rainbowfish.

Yellow Rainbowfish Stats

Before understanding the nitty-gritty and raising practices of yellow rainbows, it is imperative to be educated first on the details of proper housing and living conditions for Yellow Rainbowfishes.

Size At least 4 ft. long
Tank At least 40 gallons of water
pH 7.5-8.0
Hardness Medium dH 10-15°
Temperature 70°F to 77°F (21-25° C)


The table below shows the taxonomic ranking of Yellow Rainbowfishes.

Class Actinopterygii
Order Atheriniformes
Family Melanotaeniidae
Genus Melanotaenia
Species M. herbertaxelrodi

– Appearance: Are They Attractive?

As the name suggests, the Yellow Rainbowfish boasts a beautiful yellow scale that makes them stand out from other species. Others may have a bluish or reddish tint on top of the yellow color, which adds better aesthetics.

The obvious distinction among these species is observed between genders. Yellow Rainbowfish size is highly affected by their sex: males are more colorful, deep-bodied, and have longer anal and dorsal fins than their female counterparts.

Juvenile fish, however, do not possess the beauty that adult Yellow Rainbowfish have. They are often overlooked for their simple appearances. But once settled in their new vegetation-rich, companion-filled aquarium home, they will begin to reveal the beauty that is activated upon maturity.

The length of this yellow tropical fish is highly dependent on the sex. On average, their length ranges from 3.5 to 5 inches. The Yellow Rainbowfish lifespan, along with other species under the Rainbowfish umbrella, is approximately five years.

– Origin: Where Did They Come From?

The natural habitat and place of origin of Yellow Rainbowfish are located in Southeast Asia, particularly in the lake Tebera of Papua New Guinea. The lake is enclosed with mountainous rainforests and Yellow Rainbowfish reside on clear waters or shoals with abundant vegetation.

The practice of raising these fish in tanks began in Indonesia. To date, stories of their beauty have spanned different countries and are now sold to those who wish to raise them.

– Temperament and Behaviour

As mentioned above, Yellow Rainbowfish are peaceful shoaling species highly suited to cohabitate with other fish. This Yellow Rainbowfish behavior allows them to be perfect in community aquariums. Despite the preference for aquarium companions, they require substantial space for swimming around. These species show no predatory interest towards other species because of their small mouths.

Yellow Rainbowfish Care

There is not much demand when it comes to technicalities in raising Yellow Rainbowfish. The problem, however, is observed in the cost of maintaining the species. As observed in the table above, at least 4 feet in length would be the ideal area for housing this fish.

This is due to their active and dynamic lifestyles. Unless you are really invested in raising fish, opting to raise this fish will incur large expenses.

The water in the tank should be at least 40 gallons to house a school of fish, which is preferred by the Yellow Rainbowfish. The ideal temperature ranges from 70°F to 77°F (21°-25° C), anything lower would require a heater for their comfort.

Make sure to provide the water with a filter that can give moderate currents to keep the water flowing and the tank squeaky clean. Replace 25% of the total water volume every two weeks.

As for the pH level, anything too acidic is not advisable. Keep the pH level between 7.5 to 8 to maintain their body’s integrity as lower than the advisable level may burn their skin. For the hardness, on the other hand, they thrive in medium-hard water environments. This means a relatively fair amount of calcium and other nutrients for survival.

Lastly, make sure that the tank has enough vegetation to mimic the environment of origin of Yellow Rainbowfish. This will allow them to nibble on vegetation too as their source of food.

Tank Mates: Which Species Best Coexists With Them

Yellow Rainbowfish prefer to be in a community of fish rather than situated all by themselves. Of course, provided the requirements and standards needed for the survival of this species, companion fish must be ones that can also thrive in the same environment as them.

Below features the names of species ideal to accompany yellow rainbow fish:

  • Adelaide River Rainbowfish
  • Parkinsoni Rainbowfish
  • Neon Dwarf Rainbowfish
  • Large Tetras
  • Barbs
  • Seluang Fish
  • Danios
  • Catfish
  • Kribensis

Ideally, six or more species of the ones listed above should accompany Yellow Rainbowfish in the tank. In addition to this, yellow aquarium fish will only make slow-swimming fish anxious and nervous due to the fast and active movement of the former. Thus, fast fish must also accompany the species in captivity.

Best practices for Breeding

Yellow Rainbowfish are prolific egg layers, making rearing relatively easier. A thing to note, however, is that mature parents have a history of eating their eggs or filial cannibalism. That being said, breeders must be keen to separate or siphon the eggs from the parents. Otherwise, larval survival will not be ensured.

Ideally, there should be a separate breeding area for mature male and female Yellow Rainbowfish. This must be composed of 75% mature tank water, and the rest will be dechlorinated freshwater. Vegetation like fine-leaved plants and java moss must be maintained as this will serve as food and breeding ground for the partners.

The ritual begins as the male displays the blue mating stripe on its forehead, which is succeeded by mating and ultimately laying of eggs. Eggs usually hatch after a week. New hatchlings cannot feed themselves, nor can they defend themselves from other species and their parents intending to consume them. It is then the responsibility of the owner to watch over and feed them, which brings us to the next point.

Diet: Specific Food Requirement for Their Ages

Like humans, fish have their stages of development, and the food requirements for each phase will vary. Below features the practices for feeding Yellow Rainbowfish depending on their maturity.

1. Hatchlings or small fry

The ideal food for this stage is green water, which is simply old water exposed to the sun until algal bloom occurs. Infusoria and liquifry would be advisable food as well. None of the mentioned will cause potential choking to delicate fry.

2. Two-week Old Hatchlings

For this bunch, baby brine shrimp would be the perfect food provided.

3. Mature Yellow Rainbowfish

Mature fish do not have many complaints when it comes to food preferences. Mature Yellow Rainbowfish can feed on fish flakes, micropellets, mosquito larvae, and duckweed.


  • Yellow Rainbowfish are peaceful shoaling fish that originated in Papua New Guinea
  • This species require a substantial sized tank (at least 4 feet long) that can be filled with at least 40 gallons of water and be cleaned every two weeks
  • Ideal water temperature ranges from 70°F to 77°F (21°-25° C) with a pH and hardness of 7.5-8.0 and 10-15°, respectively
  • The size and shape of this species are affected by their sexes (males more brightly colored and deeper-bodied than females)
  • Their length spans from 3.5 to 5 inches and has an average life span of five years
  • Yellow Rainbowfish requires aquarium companions
  • You must breed mature male and female Yellow Rainbowfish separately, and you must siphon eggs from the mating ground to avoid filial cannibalism
  • Young hatchlings must feed on green water, infusoria, and liquifry
  • Two-week old hatchlings can feed on shrimp brine
  • Mature fish can handle fish flakes, micropellets, mosquito larvae, and duckweed

The Yellow Rainbowfish is one of the best species in fish tanks because of its aesthetic quality. You have to make sure to have enough resources to handle such species. Nevertheless, it will be fulfilling and exciting if you ever decide to raise one.

Their active, dynamic, and companion-seeking personality is a beautiful trait to observe, and you will certainly appreciate having them around.

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