Aquariums, Freshwater fish, Information, Rainbowfish, Species

Red Rainbowfish (Glossolepis incisus)

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by Jason Matthews



Red Rainbowfish will surely add color and energy to any tank. In this article, we will explore their origin, behavior, and care requirements, as well as their preferred tank conditions, diet, and breeding habits.

Whether you’re a beginner or an experienced fish keeper, this comprehensive guide will provide all the information you need to successfully keep and care for Red Rainbow Fish. So, sit back, relax, and dive into the fascinating world of the Red Rainbow Fish.


Scientific Name: Glossolepis incisus
Common Names: Red rainbowfish or salmon-red rainbowfish
Life Expectancy: 6-8 years
Adult Size: 15 cm (5.9 inches)


HabitatRivers, streams, and lakes
OriginNew Guinea
Care LevelModerate
DietPrimarily omnivorous
Tank LevelMid to top level
Minimum Tank Size30 gallons (113 liters)
Water pH6.5-8.0
Water Temperature72-82°F (22-28°C)
Water HardnessSoft to moderately hard water
LightingModerate to high lighting
Tank MatesPeaceful community fish such as tetras, gouramis, and corydoras

Fun Fact Corner

Here’s a fun fact about these fish that you may not know: they have a unique ability to change the color of their scales depending on their mood and surroundings. In their natural habitat, they can be found in various colors, from bright red to muted orange and even yellow.


The origin of the Red Rainbow Fish can be traced back to the rivers and streams of New Guinea and neighboring islands in the Indo-Pacific region. They are a naturally occurring species and have not been selectively bred in captivity. The unique environmental conditions in this region, such as tannins and other organic acids in the water, have contributed to developing the vibrant red coloration that has become a hallmark of this species.

Appearance & Size

The Red Rainbow Fish is distinguished by its vibrant red coloration covering most of its body. The red coloration is offset by an iridescent metallic blue or green sheen on its scales, creating a truly stunning visual effect. 

The Red Rainbow Fish has a distinct and appealing pattern of black markings along its dorsal and caudal fins. They are also known for having an elegant and streamlined body shape and a sleek and slender profile.

The size of the Red Rainbow Fish is relatively moderate, with adult individuals typically reaching a maximum length of around 5.9 inches (15 cm). This makes them suitable for various aquarium sizes, from smaller desktop setups to larger community tanks.


When it comes to the genders of the Red Rainbow Fish, it can sometimes be difficult for aquarium hobbyists to tell males and females apart. This is because the physical differences between the sexes are not always noticeable. 

There are, however, some subtle differences that can be used to distinguish between the genders. Male Red Rainbow Fish have brighter red coloration, especially on their dorsal and caudal fins and longer and more pointed dorsal and anal fins. Female Red Rainbow Fish are more rounded and less vibrantly colored than males. Observing your Red Rainbow Fish’s behavior and physical characteristics over time is the best to determine their gender


The Red Rainbow Fish are active and energetic fish constantly on the move, swimming and exploring their surroundings. They are peaceful and do not tend to exhibit aggressive behavior towards other fish species. They are also known to be curious and intelligent, making them a fun and interactive species to keep.


 When selecting Tankmates for your Red Rainbow Fish, it’s important to choose species that are compatible in terms of water conditions and behavior. 

Some good tankmates for Red Rainbow Fish include:

  • Other peaceful fish species such as tetras, rasboras, and gouramis
  • Livebearers such as guppies and mollies
  • Shrimp and snails

Tank conditions

Red Rainbow Fish is native to the slow-moving rivers and streams of Papua New Guinea, where they are used to living in soft, acidic water.

It’s important to provide them with similar water conditions to recreate their natural habitat in your aquarium. A pH range of 6.0-7.0 and a water hardness of 5-15 dGH is ideal for these fish. Maintaining a consistent temperature in the tank is also essential, with a range of 76-82°F (24-28°C) being suitable for most setups.

Red Rainbow Fish do well in well-established tanks with a good balance of beneficial bacteria. A hang-on-back filter or a canister filter will provide the necessary filtration for your tank, and water changes should also be performed to maintain water quality and remove any accumulated waste.

Additionally, providing plenty of hiding places in the tank, such as caves, rocks, and plants, is important to help your fish feel safe and secure.


The Red Rainbow Fish is an omnivorous species that eats plant and animal food. They feed on various food sources in the wild, including insects, crustaceans, and small invertebrates. An aquarium’s varied diet is essential to keep your fish healthy and promote their overall well-being.

A balanced diet for Red Rainbow Fish should include high-quality, staple flake food supplemented with frozen or live foods such as bloodworms, brine shrimp, and daphnia on occasion. You can also provide them with various vegetable-based foods, such as blanched spinach, lettuce, or peas, to add variety and nutrition to their diet.

Instead of one large feeding, feed your Red Rainbow Fish several small meals throughout the day. This will help to prevent overeating and improve digestion. Overfeeding can cause water quality issues because uneaten food decomposes and contributes to high waste levels in the tank.


Breeding Red Rainbow Fish in an aquarium setting can be a rewarding experience for experienced fish keepers. These fish are egg-layers and deposit their eggs in a spawning mop or on a flat surface within the tank.

To successfully breed Red Rainbow Fish, it’s important to provide them with ideal breeding conditions. This includes a spacious, well-planted tank with a stable water temperature and pH, good water quality, and plenty of hiding places. 

When the male Red Rainbow Fish is ready to breed, he will display courtship behavior, and the female will lay her eggs in a safe location. The eggs will hatch in a few days, and the fry can swim freely in about a week. Once the eggs have been laid, the parents must be removed from the tank because they may become aggressive and will attack the fry.


Diseases are a common concern for all pet fish species, including Red Rainbow Fish. These fish are hardy and resistant to many common fish diseases; it’s important to be aware of the signs of the disease and take proactive measures to prevent and treat any issues that may arise.

Ich, fin rot, and bacterial infections are all common diseases that can affect Red Rainbow Fish. Cloudy eyes, clamped fins, loss of appetite, and abnormal swimming behavior are all symptoms of these diseases. Maintaining good water quality, providing a varied diet, and avoiding overcrowding in the tank all help to prevent disease in Red Rainbow Fish.

If you suspect your Red Rainbow Fish has a disease, you must act quickly to address the problem. This could include performing water changes, medicating the water, and feeding the fish a nutritious diet. In some cases, it may be necessary to separate the affected fish from the rest of the tank to prevent the spread of the disease.


Jason Matthews

My name is Jason Matthews, and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

Jason aquariume

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