Rainbowfish is group of small and usually colourful fishes found in the southern hemisphere. They did not grew popular among aquarists until fairly recently, which is actually a bit strange considering their beauty and sturdiness. Some species stay below 3 cm in length even as adults, while other species can attain a length of up to 20 cm. An additional plus with Rainbowfish is that they leave plants alone – they will not eat them nor uproot them. Rainbowfish is also an excellent choice for aquarists who like their fish to spawn in the aquarium.

Rainbowfish belong to a subfamily named Melanotaeniidae and are found in Australia and New Guinea, as well as on some of the Southeast Asian Islands. Rainbowfish are closely related to the Blue-eyes of the subfamily Pseudomugilinae and both subfamilies belong to the same family, Melanotaeniidae, according to a taxonomic revision made by Joseph Nelson in 2006. The order Atheriniformes –  the order to which Rainbowfish and Blue-eyes belong –  has undergone a lot of changes during recent years and is expected to see some action in the years to come as well.

Since Rainbowfish are peaceful creatures they can be kept in community aquariums with other non-aggressive species. Really small species can however find it hard to compete in an aquarium with larger species and should therefore be kept in their own aquarium, or together with other really small and peaceful species.

Rainbowfish are schooling fish and should be kept in groups consisting of at least six individuals, preferably no less than 10-15. This is not only beneficial for the fish; a large school of shimmering Rainbowfish is also much more stunning to look at than a few shy individuals that spend most of their time hiding. Keeping several males together will also make them develop more vibrant colours since they need to compete with each other for female attention.

Rainbowfish (M. boesemani) Copyright fishaliciousfish.blogspot.com

One of the reasons behind the scarcity of Rainbowfish within the hobby is probably the fact that young Rainbowfish look quite dull. Fish stores usually sell small Rainbowfish that have yet not developed their true colours. If you buy young Rainbowfish and take good care of them, they will mature and develop their adult colouration.

It is unfortunately quite common for fish stores to place their fish in aquariums that are too small or too crowded; conditions that can easily make even an adult Rainbowfish look pallid and unappealing. Barren aquariums without suitable hiding spots, or aquariums with aggressive species, can also make the Rainbowfish dampen its colours, since it will feel highly stressed.

All the various Rainbowfish species are quite similar when it comes to feeding requirements, desired water chemistry, temperature, breeding habits etcetera. There are however minor differences between the many species so it is always a good idea to research your particular species before you bring them home. Generally speaking, the horizontal length of the aquarium is much more important than the depth, since Rainbowfish spend most of their time near the surface and rarely venture any deeper down. As mentioned above, the size varies considerably between the different species and it is therefore impossible to recommend an aquarium size.

Keepers of Rainbowfish usually opt for a dark substrate in the aquarium and strong lighting since this make the Rainbowfish look more vibrant. The natural Rainbowfish habitat is filled with aquatic plants and rainbows will therefore appreciate a planted aquarium. There should also be some open space available for these active and energetic fishes to swim around in. Keep the aquarium closed to prevent the fish from jumping out of the water.  

Rainbow Fish Articles

Australian Rainbow fish - Breeding and raising the Australian Rainbow fish, Pseudomugil gertrudae and Pseudomugil signifer.
Feeding rainbowfish - A guide to feeding rainbowfish
Rainbowfish - An introduction to Rainbowfish
Rainbowfish Aquarium - Information about ho to setup an aquarium for rainbowfish.
Rainbowfish breeding and spawning - Learn how to breed these fish.
Rainbowfish Diseases - Information on different diseases that commonly infect these fish.
Keeping Rainbow fish - Information about how to keep rainbow fish and avoid some common problems.

Below you can find information about different species off rainbowfish.

Rainbowfishes in Australia

Cairns Rainbowfish
Threadfin Rainbowfish
Lake Eacham Rainbowfish
Exquisite Rainbowfish
Murray River Rainbowfish
Slender Rainbowfish
MacCulloch’s  Rainbowfish
Black-banded Rainbowfish
Pygmy Rainbowfish
Western Rainbowfish
Chequered Rainbowfish
Eastern Rainbowfish
Desert Rainbowfish
Banded Rainbowfish
Ornate Rainbowfish

Rainbowfishes in New Guinea

Axelrods Rainbowfish
Bleher’s Rainbowfish
Bulolo Rainbowfish
Higlands Rainbowfish
Silver Rainbowfish
Barred Rainbowfish
Lorentz’s Rainbowfish
Sentani Rainbowfish
Red Rainbowfish
Spotted Rainbowfish
Sepik Rainbowfish
Tami River Rainbowfish
Ramu Rainbowfish
Lake Wanam Rainbowfish
Threadfin Rainbowfish
Northern Rainbowfish
Ayamaru Rainbowfish
Angfa Rainbowfish
Arfak Rainbowfish
Boeseman’s Rainbowfish
Corona Rainbowfish
Waigeo Rainbowfish
Serong Rainbowfish
Goldie River Rainbowfish
Lake Tebera  Rainbowfish
Irian Jaya Rainbowfish
Strickland Rainbowfish
Yapen Rainbowfish
Lake Kutubu Rainbowfish
McCulloch’s  Rainbowfish
Mayland’s Rainbowfish
Misool Rainbowfish
Mountain Rainbowfish
Ogilby’s Rainbowfish
Oktedi Rainbowfish
Parkinson’s Rainbowfish
Lake Kurumoi Rainbowfish
Pima River Rainbowfish
Dwarf Neon Rainbowfish
Fly River Rainbowfish
Red Striped Rainbowfish
Van Heurn’s  Rainbowfish

Blue-eyes

Kiunga Blue-eye
Popondetta Blue-eye
Blueback Blue-eye
Forktail Blue-eye
Spotted Blue-eye
Inconspicuous Blue-eye
Cape Blue-eye
Honey Blue-eye
New Guinea Blue-eye
Swamp Blue-eye
Paska’s Blue-eye
Vogelkop Blue-eye
Pacific Blue-eye
Delicate Blue-eye
Red-finned Blue-eye