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Turquoise Rainbowfish Care, Lifespan, Breeding & More

Rainbowfish are one of the most exotic types of aquarium fish to pet. And among this species, Turquoise Rainbowfish look the brightest and eye-catchy with their deep blue color combinations.

So, Turquoise Rainbowfish is one of the most stunning fish found in lake Kutubu. With 4.9-inches in length, they possess a brilliant color-changing characteristic. They are best kept as schooling fish in a 30–60-gallon tank with an omnivore diet and proper water conditions.

Species Overview

Level of CareModerate
AppearanceThey usually have a cobalt blue or a teal-colored tone from the top, which tends to fade into a greenish, silverish, or yellowish hue at the bottom area.
TemperamentAggressive or violent if not kept with a suitable tank mate.
Life Expectancy5-8 years
Tank Size30-60 gallon
Tank EnvironmentHard alkaline water condition with dense plantation
Tank MatesPeaceful

Turquoise Rainbowfish is one of the most famous freshwater fish species, which are only found in Lake Kutubu and its outlet of southern Papua New Guinea, located in the Southern Highlands.

The natural habitat of the Lake Kutubu Turquoise Rainbowfish possesses very clear water with plenty of limestones obtained from underground springs. And that is why the pH level of its natural habitat is slightly alkaline.

Also known by its scientific name, Melanotaenia Lacustris, Turquoise Rainbowfish is very popular for its unique body type. The body of these fishe is quite long and tends to deepen as soon as they age.


The unique characteristics of this fish are that the head of an older male Turquoise Rainbowfish is not at all going to follow the round contouring lines of its body. Instead, it will come up with a much narrower and triangular head.

Their eyes deserve a special mention here, as it is large and significant. Also, Turquoise Rainbowfish have quite impressive dorsal fins.

Besides, the Lake Kutubu Turquoise Rainbowfish are capable of having many colors. However, they are famous for their exotic dark blue hue. Thus, the common name of Blue Rainbowfish comes from their very appearance.

These fish usually have a cobalt blue or a teal tone from the top, which tends to fade into a green, silver, or yellow color at the bottom area.

Beginning from the rear portion of their tail, Turquoise Rainbowfish usually have a thin cobalt blue stripe, which tends to disappear near the mid-portion of their body.


Turquoise Rainbowfish are usually not small. Instead, they have a moderate length. These fish typically grow up to 4.9-inches or 12.47 cm in length.


These Melanotaenia Lacustris species can be tagged as community fish. They are playful by nature, as well as exuberant.

These Turquoise Rainbow fish are more susceptible to becoming aggressive and territorial, based on the other members in a community tank.


The fish, Turquoise Rainbows, are much hardy by nature. So, these fish usually live much longer than many other freshwater fish species.

Generally, the Turquoise Rainbowfish comes with an average life span of about 5 years. However, these aqua animals can also live up to 8 years in a well-maintained tank subject to proper care and diet.

Tank Requirements

Blue rainbowfish melanotaenia lacustris tend to perform extreme swimming activity. So, you need to ensure that you are offering them a proper level of care within your tank. The aquarium that you will pick for this fish needs to have enough space in it.

Moreover, make sure the tanks you choose for your rainbowfish melanotaenia lacustris have a proper cover to keep them secured in the tank.

The Lake Kutubu rainbowfish melanotaenia lacustris usually requires cleaner water parameters for a healthy life. Thus, it is better to use an effective water filter in the aquarium to maintain proper water movement in the tank.

These Lake Kutubu rainbowfish melanotaenia lacustris must have a soft substrate to ensure better care in the tank. At the same time, make sure the substrate is dark enough so that these fish can display better coloration. Also, they prefer dense vegetation and bogwood, which helps in perfectly mimicking the natural habitat condition of Papua New Guinea.

The rainbowfish melanotaenia lacustris usually prefer a well-planted aquarium for their better care. This Rainbowfish species easily tolerates hard and alkaline water conditions.

These fish also prefer to stay under two hours of sun rays. It helps them acquire more healthy growth.

Tank Setup

The tank setup for your Turquoise Rainbowfish requires special attention to offer a proper level of care to this exotic fish. The rainbowfish melanotaenia lacustris survive well in a properly setup tank having the right temperature and appropriate pH range.

So, here is how you can ensure a proper tank setup for your Turquoise Rainbowfish.

  • For delivering better care to the young rainbowfish melanotaenia lacustris, 30-gallon tank size is much suitable. For keeping adult-size schooling rainbowfish melanotaenia lacustris at your home, you require a 60-gallon tank.
  • Make sure that you are maintaining a hard and alkaline water condition for them in a community tank. The pH range needs to be within 7-8.5.
  • The hardness range of tank water must lie in the range of 8-25 dGH.
  • Use a small sand gravel substrate with a darker color to let your rainbowfish glow brightly in the tank.
  • Use a filter to maintain a feeble yet adequate movement of water in the aquarium.
  • These fish usually prefer a moderate temperature. Thus, try to maintain the temperature within the level of 70-79 ℉.
  • There is no need for bright lighting in the tank of rainbowfish. You can apply a moderate to normal intensity of illumination in the tank for better care of your fish.
  • These fish love to dwell in dense vegetation. Thus, you can add a moderate amount of plants to the tank while leaving some free spaces for them to swim around at ease.

Turquoise Rainbowfish Care

Turquoise Rainbowfish are not at all difficult to care for in an aquarium. This Lake Kutubu fish species typically need a clean water quality for maintaining their best health.

In case the tank is densely stocked, then it is necessary to perform more frequent water changes. It is better to change at least 25-50% of tank water weekly.

The rainbowfish are usually too hardy to be susceptible to frequent illness. However, if they are not cared for properly, they can catch some prevalent fish diseases.

Adding any new fish, aquarium plants, substrate, or tank décor can cause bacteria to build up in the tank. However, the best part about Turquoise Rainbowfish is that they will not easily be the reason for an outbreak of diseases in the community tank. Their fish disease is often limited to one species.

So, to offer them a very healthy life in your tank, you need to provide this freshwater fish with a proper amount of balanced diet. Also, make sure the water is clear and stable enough to acquire an appropriate level of immunity.

Food & Diet

Melanotaenia lacustris are usually not at all difficult to feed in the tank. These Rainbowfish mostly thrive on an omnivore diet, which means they readily accept all types of necessary fish food item.

This freshwater rainbowfish melanotaenia lacustris usually feed on small crustaceans, algae, and insect larvae in their natural habitat site. During captivity, they will readily accept high-quality flake food or pellet foods.

To maintain a variety in their food habits, Turquoise Rainbowfish will also require live food components in their diet. It is better to treat your rainbowfish melanotaenia lacustris with fish foods like brine shrimp, tubifex worms, or bloodworms. Some of their diets can also contain vegetable foods for serving them better nutrition to develop brighter colors.

Usually, Turquoise Rainbowfish have smaller throats. So, you should feed them in smaller quantities at least 2-3 times a day. Also, make sure that you provide them with the food they can easily consume within less than 5 minutes.

Tank Mates

Melanotaenia lacustris fish are not at all aggressive if they are housed with compatible tank mates. However, these Lake Kutubu Rainbowfish can suddenly get violent and aggressive if they find out that their aquarium mates are not very impressive or suitable.

Melanotaenia lacustris are best kept with their own species or other types of rainbowfish. You must add these Turquoise Rainbows with fish having a similar temperament and size.

Turquoise Rainbowfish species are typically the shoaling ones. Thus, you need to pick the perfect ratio for keeping them together in your tank. Also, you can keep a single-sex school of these Blue Rainbows to see a much significant improvement in their coloration.

If you keep a group of 5 Turquoise Rainbowfish together, it is better not to mix the sexes. But for schools of 6 fish, you can add 3 males and 3 females in the tank.

Also, if you want to keep a group of 8 Melanotaenia Lacustris, it is recommended to house 3 males and 5 females together. In the case of a school of 10 specimens, accommodate a similar number of males and females in your fish tank.

However, if you are thinking of adding this community fish to a large community tank, you can easily house them with other peaceful tank buddies. But do not house them with semi-aggressive aggressive or larger ones.

Since these fish grow large and stay in a school, they can easily become a reason of stress for their other sensitive tank mates.

So, here is a list of the most compatible tank mates of Turquoise Rainbowfish.

  • Other rainbowfish
  • Danios
  • Barbs
  • Gobies
  • Characins
  • Corydoras


Juvenile turquoise rainbowfish

For achieving the successful breeding of Blue Rainbowfish, you need to setup an appropriate tank. The breeding tank of Lake Kutubu Turquoise Rainbowfish must have soft acidic water conditions.

Also, for a proper tank setup, you need to ensure that you are adding enough filtration to the tank with a sponge filter.

You can consider keeping a spawning mop in the tank or fine-leaved plants to offer your Turquoise rainbowfish enough space for laying eggs.

To achieve success in breeding a school of Lake Kutubu Rainbowfish, 2 females and 3 males will be pretty suitable. It is vital to condition these freshwater fish in the tank with a proper amount of live foods and plant-based foods.

As the female Turquoise rainbowfish melanotaenia lacustris tends to develop an interest in spawning, the male ones will show their intense coloration and allure the female fish to swim to the spawning site.

As soon as the female specimens lay fertilized eggs, make sure to remove the spawning mops or plants to prevent the parent fish from eating away the eggs.

The fish usually continue with their spawning for some days. However, with time, you’ll be able to see a decreasing number of eggs laid by the female specimens.

The fry of this fish species typically hatches after a few days of egg-laying. During the initial days of their birth, try to feed your rainbowfish melanotaenia lacustris fry enough amount of infusoria or liquid fry food for their better nourishment.

After a few more days, you can offer them small live foods and crustaceans for better care.

During breeding, it is much essential to stay careful and attentive to avoid any crossbreeding. Usually, fish born out of crossbreeding tend to lose their coloration. Thus, setup an entirely different tank for the breeding purpose of rainbowfish melanotaenia lacustris.

Interesting Facts

There exists quite interesting information about Turquoise Rainbowfish, which you must know before bringing them to your house.

Well, here is a list of some fantastic pieces of information about them.

  • Melanotaenia lacustris have brilliant characteristics to change their coloration throughout the day. They can easily change their colors in a matter of seconds and showcase a variety of shades throughout the day, resembling the color of a rainbow.
  • Their fins tend to have a slightly bluish tint with black edges when they are ready for spawning.
  • In every two years at Lake Kutubu, Melanotaenia lacustris gets reduced in numbers. The water comes up from the bottom of the lake, which causes oxygen deficiency in the water, killing a massive number of Blue Rainbowfish.
  • Due to the movement of the water upward, gill nets, logging and oil drilling, and outboard motors, the Lake Kutubu Rainbowfish is listed as a “Vulnerable” fish species in the IUCN Red List of Threatened species.
  • The mature male Turquoise Rainbowfish show a vibrant coloration and are more aggressive than the female ones.
  • These Rainbowfish are usually skilled jumpers and always tend to jump out of the tank. Thus, you need to affix a tight cover for the tank.

Frequently Asked Questions

Where to buy turquoise rainbowfish?

Turquoise Rainbowfish are not at all tough to find in your nearby store for pet animals that supplies a wide range of aquarium fish. They are sold with a local common name, Lake Kutubu rainbowfish or Blue rainbowfish.

However, these Turquoise Rainbowfish are a bit pricey than the other rainbowfish species. You can also look for Turquoise Rainbowfish in your nearby hobbyist store or place orders for these fish on any online store for fish.


Turquoise Rainbowfish are pretty suitable for keeping and caring in a community tank. They are not much difficult to care for like the other rainbowfish species.

However, they can be pretty sensitive to frequent water changes. And that is why, to offer your Turquoise Rainbowfish enhanced care, provide them a pristine and stable water condition.

Besides, to offer them a proper level of care, you need to have a moderate to intermediate level of experience in the fish-keeping hobby.

Also, ensure an appropriate rate of filtration to keep the water clean. Moreover, make sure you are housing them with suitable tank companions only so that they can stay happy and healthy for a long time with you.