Rainbowfish: The Ideal Fish for Your Aquarium

The Rainbowfish is one of the most beautiful freshwater species that exists. The high density of the colors of your skin can capture the attention of anyone. For those who are dazzled by the chromatic arcs that are drawn in the sky, this is the ideal fish for their aquariums, as it is a species, par excellence, ornamental. Rainbowfish are a type of fish that have been around for centuries and are one of the most popular types of freshwater aquarium fish.

They come in many different colors, such as orange, blue, red-orange, green, or pink. There is also a variety called dwarf rainbowfish which only grow to about 1 inch long. Rainbowfish can be found all over the world but they’re primarily located in Australia and New Guinea. The first known mention of this species was by Francis Buchanan White who described them as “a beautiful little gem” when he saw them at the Cape York Peninsula on Queensland’s northern coast in 1878. Not much is known about their natural habitat due to their popularity as aquarium pets.


This name honors its discoverer Melanus Boeseman. The figure of who gave birth to this fish does not detach from the ways of calling them. Many times when it refers to this species, credits are usually given to the work of the discoverer, so it is not strange that know it as Boeseman’s rainbowfish.

Characteristics of Rainbowfish

The body of the rainbowfish has a flat oval appearance, compressed on the sides. The rainbowfish features a very well-structured symmetry, as there is no differentiation between the dorsal area of ​​the fish and the belly area. Both denote a similar and well-schemed appearance. However, over time, the back presents a small bulge, this is a feature that allows knowing the age of the fish.

The appearance of that prominence usually appears when they are very old. This fish has three fins: an anal fin and two dorsal fins. The anal fin is a clear continuation of your body since it starts from the middle part, that is, in the pelvic area. This fin has an important function because with it the fish has the possibility of acquiring momentum and speed to swim.

While the dorsal fins are abutting the caudal zone they direct the displacement. Although the fins of the rainbowfish do not present an excessive size, that does not detract from their ability to swim.


The rainbowfish is a species that presents small proportions. The size of the rainbowfish goes between 6 centimetres and 12 centimetres approximately. This feature makes it one of the favorite fish for ornamental breeding. Since they do not acquire large volumes and can be kept in medium aquariums. However, there are subspecies within the Melanotaeniidae family that tend to grow much more. Well, it has been shown in some specimens that reach up to 20 centimetres in length. You may also like to read Angelfish.


The coloration of the rainbowfish is one of the unique and distinctive characteristics of this spectacular species. The scales of this type of fish refer to the range of colors that have a light phenomenon that is projected in the sky commonly called a rainbow. Hence, this variegated feature coincides and is the consequence of why it is referred to in that way.

Violet, turquoise blue, yellow, orange, and red are the degradations that they upholster in the form of faint degradations. The colors of the rainbowfish have variability in the tonalities. The chromatic difference has a reason and is that it is due to the sex of the animal. To diagnose that a rainbowfish is male, it must be taken into account that the male has intense red scales. You may also like to read goldfish

Its appearance gives the impression that it was varnished with some type of oil. They shine many more than the female because these tend a little more opaque. In the case of females, the less luminescent aspect is not the only feature that varies generically. The body is crossed by a thin blackened line that divides the body into 2. A line that goes from its tail fin and ends in the highest part of it.


Rainbowfish usually inhabit sweet aquatic environments. Not all rivers are favorable for the existence of Rainbowfish. They live in certain rivers with specific characteristics. For example, lakes or rivers must have a condition that corresponds to the measurements or the degree of pH in the water. For the water to be optimal and to house the rainbowfish without any problem, it must have ranges of no more than 6 to 7 pH, since the most typical for this type of fish is living in a neutral environment.

It should be noted that as long as the water is more clear and clean, the conditions, development, and health of the rainbowfish will be favorable. In addition, these freshwater fish do not usually swim in very deep areas, therefore, these may be the shores of lakes or rivers or shallow freshwater. Another requirement that characterizes the rainbowfish habitat is that they have abundant plants. The water has a temperature that averages between 22 to 26 degrees Celsius.


The reproduction of the rainbowfish presents important facets, the first place is the chain spacing of the eggs. Then the hatching of the same finally produces the release of the fry. For this process to take place, fish must first go through a stage of courtship. The process of incubation of the rainbowfish lasts for 8 days. Several factors affect the hatching of eggs, the main one is the water temperature, ideally around 25 degrees Celsius.

The number of eggs that a female rainbowfish can spawn is between 100 to 200 eggs. These are mostly placed between plants since this is the place used by rainbowfish for mating. There is another outstanding feature about the eggs of this species, and that is that they have an adhesive layer, that is, they can stick to the leaves of plants or rocks.


The mouth of the rainbowfish has a very particular feature, it is very narrow. So they are fish that are characterized by having very small bites, but that does not prevent them from being great food eaters. Well, if there is something that these fish have, it is a very voracious appetite. In addition, the mouth has an ascending inclination, which is closely related to the type of behavior that has at the time of eating. The rainbowfish devour food they find on the surface. The position of their mouth affects that they are unable to eat any type of food that is resting on the substrate.


Are rainbow fish easy to keep?

Yes, rainbow fish are relatively easy to keep. They are a hardy species and can tolerate a wide range of water conditions. As long as the tank is well-maintained, they should be able to live comfortably in the aquarium.

Are rainbow fish good community fish?

Rainbow fish are a great choice for community tanks. They are peaceful, vibrant, and relatively hardy fish that can add color and life to any aquarium. Rainbow fish prefer to be kept in groups of six or more, so they should be added to the tank in at least this number. They are active swimmers and will appreciate plenty of open swimming space within the tank.

How big does a rainbow fish get?

Rainbow fish, also known as Melanotaenia, can grow to about 6 inches in length. They are typically found in lakes and streams of New Guinea and Australia, where they inhabit large schools. As a result, they need to be kept in aquariums with plenty of space for them to swim around and socialize.


There is a lot to learn about this aquatic animal, but hopefully, the tips and facts in this guide have helped you understand what rainbowfish are. If not, don’t worry! The internet has plenty of information on these colorful fish that will help make your next decision easier. Whether you’re purchasing one as an aquarium pet or looking for more information on where they live worldwide, enjoy your search!

 As a Reference: Wikipedia

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