Tips on Keeping Rainbowfishes

These small and colorful fish do well in heavily planted tanks.

Rainbowfish refers to a group of small and colorful fishes native to the southern hemisphere, specifically Australia, New Guinea, and some islands in Southeast Asia. They belong to the Melanotaeniidae subfamily. Some species of rainbow fish reach a length of 3 cm as adults, while other species can reach 20 cm in length. 


Rainbowfish are ideal for planted tanks since they leave aquatic plants alone. They are also an excellent choice for hobbyists who want their fish to spawn in the aquarium. Being passive fish species, they can be kept in community tanks with other species that are non-aggressive.

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Boesemans Rainbowfish

Parkinsons Rainbowfish 

However, if you have really small species of Rainbowfish, it is better to place them in an aquarium together with other small and non-aggressive species.


Being a schooling fish, Rainbowfish should be kept in groups of at least six, preferably no less than 10-15. Keeping several males in the same tank will also bring out their vibrant colors, which is an attempt to attract female attention. 
While still young, Rainbowfish appear quite dull, thus they are not as attractive compared to other fish species. Their distinct body coloration will come out once they mature and with proper care.

Living Parameters of Rainbowfish

Rainbowfish can be kept even in small aquariums. The size of your tank will depend on how many rainbowfishes you want to keep, and if you want to put in other species of fish. You should also keep in mind that maintaining water quality is a challenge in a small aquarium. 

A 10-gallon tank can comfortably keep up to 15 Rainbowfishes, especially if you choose the smaller species such as Pygmy Rainbowfish or Dwarf Rainbowfish. A larger group of small fishes, or up to 15 medium-sized Rainbowfish species, can be housed in a 20-gallon aquarium. About 15 large species of Rainbowfish can be accommodated in a 40-gallon tank. 

To minimize stress and make your fish more secure, you need to put in aquarium decorations to create lots of hiding places. Live plants, like Java moss and Java fern, are favorite spawning sites for Rainbowfish. 

The water conditions inside the tank are highly dependent on what Rainbowfish species you are keeping. Some species are adapted to soft and acidic water, while others need alkaline conditions. However, many species are quite adaptable and are able to thrive well in water pH of 6.5-7.5 and a water hardness between 0-100 ppm. Ideal water temperature for Rainbowfish ranges from 22-28C (72-82F).

Feeding Rainbowfish

Rainbowfish are primarily surface feeders, thus you need to give what they can consume in a short time since uneaten food will sink to the tank’s bottom and pollute the water. It is better to divide their daily ration into several meals a day to preserve the water quality of your tank. 

Rainbowfish are omnivores, which means they get sustenance from a wide variety of animal and plant sources. Thus you can combine high-quality flake food with mosquito larvae, earthworms, brine shrimp, and daphnia. It is recommended to give live food than dry and frozen food. You can also give fresh vegetables. 

Peter Hartono is the founder and CEO of Just Aquatic– a proud Australian company that offers homegrown aquatic plants and aquarium supplies carrying top of the line brands including API, biOrb and Exo Terra. To find out more of our exciting offers and promotions check out our Facebook page and follow us on Twitter at @justaquatic
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Fish · Freshwater Fish