Rainbowfish are common freshwater community fish, but are you aware of how many species are out there? All members of the Melanotaeniidae family, rainbowfish are a wonderfully diverse group of fishes that are native to the islands of Australia, New Guinea, Indonesia, Sulawesi, and Madagascar.
Almost all rainbowfish species are community fish that get along with other non-aggressive freshwater fish species in an aquarium. Keep in mind, fish from different parts of the world will often have different water quality requirements, so not all species need the same water parameters.
There are many species on this list that are endangered or threatened in the wild. Here are some of the most colorful ones available from fish retailers.
Species Characteristics
Rainbowfish are classified by their elongated premaxillary teeth. They live in freshwater, including rivers, lakes, and swamps. They prefer to live in planted areas and reproduce by laying eggs. Most rainbowfish species prefer schooling together in a small group. There are various sizes and body shapes in rainbowfish.
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Boesemani Rainbowfish
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One of the most recognized rainbowfish in the aquarium hobby, the Boeseman's or Boesemani rainbowfish has a two-toned color with a blue/purple head and an orange/red back end. These rainbowfish are very easy to care for and are a common fish in many tropical community aquariums because they are hardy and able to handle various water parameters. They do well in groups, and the males' color will often get brighter when they are getting ready to spawn.
Species Overview
Scientific Name: Melanotaenia boesemani
Life Span: 5 years
Length: 4 inches (10 cm)
Physical Characteristics: Wide body, blue/purple head with orange/red back end
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Axelrod's Rainbowfish
Shirlie L Sharpe
(image from previous publication)
The Axelrod, or Axelrodi rainbowfish, is named after tropical fish expert Herbert Axelrod. This species of rainbowfish has a lighter colored body with a blue-tinged abdomen. The Axelrod rainbowfish prefers slower moving waters, mimicking the gentle streams of their native waters in the Yungkiri Stream of Papua New Guinea.
Species Overview
Scientific Name: Chilatherina axelrodi
Life Span: 5 years
Length: 4 inches (10 cm)
Physical Characteristics: Wide body, light blue in color and horizontal dark bar along their sides
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Desert Rainbowfish
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Desert rainbowfish, native to Australia, have silvery-white females and white males with purple or green-tinged fins. Due to their limited range, they have very specific water quality requirements. A stark color variation compared to many more brightly colored rainbowfish species, this one may more easily hide in lighter-colored décor and is easier to see in darker environments.
Species Overview
Scientific Name: Melanotaenia splendida tatei
Life Span: 5 years
Length: 4 inches (10 cm)
Physical Characteristics: Wide body, white to silver body with some green or purple on fins, depending on sex
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Madagascan Rainbowfish
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A note to fish keepers interested in the Madagascan rainbowfish: this species has a preference for low pH water. Their native habitats are characterized by extremely soft freshwater, with low pH and tannin-stained water. These rainbowfish have a silver body with yellow fins, and males are more saturated with color than females. The Madagascan rainbowfish may do well with South American cichlids with similar water quality tolerances, such as discus and angelfish, and they like stronger currents in their tanks.
Species Overview
Scientific Name: Bedotia madagascarensis
Life Span: 5 to 11 years
Length: 4-6 inches (10-15 cm)
Physical Characteristics: Thin body, yellow/tan body with black bar along sides and belly with re-tipped fins
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Banded Rainbowfish
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The banded rainbowfish is a popular species of rainbowfish, given their bright coloration and peaceful nature. Native to northern Australia freshwaters, males will have wider, more colorful bodies and a humped forehead. Both males and females have brightly-colored fins with a darker stripe along their midbody. This species prefers being in small groups in planted tanks. Like some other species, males will become aggressive during breeding.
Species Overview
Scientific Name: Melanotaenia trifasciata
Life Span: 5 to 8 years
Length: 6 inches (15 cm)
Physical Characteristics: Wide body, silver with red/orange/gold stripes and red tail
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Threadfin Rainbowfish
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In addition to stark differences in their required pH and temperature, the threadfin rainbowfish has a very unique body and fin shapes. They prefer water that is soft to moderately hard, slightly acidic (pH 6.0 to 7.0), and with a temperature of 73 to 84 F (23 to 29 C). They are significantly smaller than other species of rainbowfish, with thin bodies and long extensions on the dorsal and anal fins on males. In addition to their elongated fins, males have faint vertical stripes with red/orange caudal fins.
Species Overview
Scientific Name: Iriatherina werneri
Life Span: 3 to 5 years
Length: 2 inches (5 cm)
Physical Characteristics: Narrow body, red sides, males have elongated black dorsal/anal fins and red-tipped tail fin
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Celebes Rainbowfish
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The Celebes rainbowfish is a smaller, more slender species of rainbowfish. This species likes to be kept in large schools of eight to 10 fish, so be sure to plan your aquarium accordingly so that you have enough room for everyone. Celebes rainbowfish have a unique fin shape with two dorsal fins colored yellow/golden and black, and a translucent body.
Species Overview
Scientific Name: Marosatherina ladigesi
Life Span: 3 to 5 years
Length: 3 inches (8 cm)
Physical Characteristics: Narrow body, translucent main body with accented fins with yellow/black, and blue bar along the lateral line
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Neon Rainbowfish
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The neon rainbowfish is one of the smallest rainbowfish species in the commercial market. Given their smaller size, they like to be in larger groups of 10 or more individuals. They are very picky about their water quality parameters, so be sure to pay special attention to your water tests if you are adding a bunch of fish at once. They are named for their neon blue and green coloration, which can present as a brilliant flash in your aquarium as they all school together.
Species Overview
Scientific Name: Melanotaenia praecox
Life Span: 3 to 4 years
Length: 2.5 inches (6 cm)
Physical Characteristics: Wide, light-colored body with flashy green/blue accents, and red on fins
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Lake Kutubu Rainbowfish
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The Lake Kutubu rainbowfish is named for their origin at Lake Kutubu in Papua New Guinea. This species of rainbowfish is known for their jewel-tone blue, yellow and/or turquoise appearance. Like most rainbowfish species, the males tend to be more vibrantly colored than females.
Species Overview
Scientific Name: Melanotaenia Iacustris
Life Span: 5 years
Length: 5 inches (12 cm)
Physical Characteristics: Wide, light-colored body with flashy green/blue accents
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Red Irian Rainbowfish
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The red rainbowfish, or red Irian rainbowfish, originates from New Guinea’s Tami River and Lake Sentani. Males can be differentiated from females by their bright red coloration with high rounded back. In contrast, females have silver bodies with tints of yellow and green.
Species Overview
Scientific Name: Glossolepis incisus
Life Span: 5 years
Length: 6 inches (15 cm)
Physical Characteristics: Wide body, males are red/orange while females are lighter in color
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Lake Wanam Rainbowfish
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Although the Lake Wanam rainbowfish is named for their origins in Lake Wanam in Papau New Guinea, you are very unlikely to find any remaining in their home waters. The Lake Wanam rainbowfish is listed as critically endangered and not common in the hobby, and only sold through specialized breeders. As with any fish species you are looking to purchase, always consider if your fish is coming from a breeder or collected from wild stock.
Species Overview
Scientific Name: Glossolepis wanamensis
Life Span: 5 years
Length: 3 inches (8 cm)
Physical Characteristics: Wide body, darker color with tan/orange/red stripes along their bodies
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Forktail Rainbowfish
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The forktail rainbowfish is a small, slender species of rainbowfish with blue eyes and namesake forked tail. Their colors brighten during breeding season, with the males becoming brilliantly yellow. Given their small size, this species really likes being in large groups with lots of plants to hide in.
Species Overview
Scientific Name: Pseudomugil furcatus
Life Span: 3 years
Length: 2.5 inches (6 cm)
Physical Characteristics: Slender body, blue eyes, clear body with yellow/black accents
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Crimson-Spotted Rainbowfish
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Also known as Duboulay's rainbowfish, the crimson-spotted rainbowfish is so named for the characteristic red spot on both sides of their head. Their red coloration continues as red/orange speckles, which may conjoin to form lines, along their body sides. They are native to Australia and have been released into swamps and rivers to help combat mosquitos by eating the aquatic mosquito larvae.
Species Overview
Scientific Name: Melanotaenia duboulayi
Life Span: 3 years
Length: 4.5 inches (11 cm)
Physical Characteristics: Wide body, grey/black body with red/orange spots
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Murray Rainbowfish
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The Murray River rainbowfish, also known as Murray rainbowfish or Australian rainbowfish, has more subtle colors, often being a soft rainbow of blue, green, yellow or silver. Male Murray River rainbowfish will have a bright orange stripe on their back end when they are getting ready to spawn.
Species Overview
Scientific Name: Melanotaenia fluviatilis
Life Span: 3 years
Length: 4.5 inches (11 cm)
Physical Characteristics: Wide, silvery body with green-tinged scales, fins may have yellow, red, or orange pigmentation
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Redfin Dwarf Rainbowfish
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The redfin dwarf rainbowfish has a unique appearance with black stripes and vibrant red/orange tinged fins. Native to Australia, this rainbowfish can tolerate a wide range of water quality parameters, and they breed readily in captivity.
Species Overview
Scientific Name: Melanotaenia maccullochi
Life Span: 3 years
Length: 3 inches (8 cm)
Physical Characteristics: Wide, silvery-green body with black horizontal stripes, red/orange fins
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Parkinsoni Rainbowfish
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The Parkinsoni rainbowfish is a mix of silver and vivid yellow colors. Depending on the individual, they may have a lot of yellow pigmentation on their sides or only in their fins.
Species Overview
Scientific Name: Melanotaenia parkinsoni
Life Span: 5 years
Length: 5.5 inches (14 cm)
Physical Characteristics: Wide body, silvery-green body with black horizontal stripes, red/orange fins
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Spotted Blue-Eyed Rainbowfish
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The spotted blue-eyed rainbowfish, also know as Gertrude's spotted rainbowfish, is a small species of rainbowfish that has a unique fin appearance with black spots and vivid yellow tint. As the name implies, their eyes are ringed with blue, giving them a very vibrant appearance. This species of rainbowfish is very small, so they do best in schooling groups of six or more fish.
Species Overview
Scientific Name: Pseudomugil gertrudae
Life Span: 12-18 months
Length: 1.5 inches (4 cm)
Physical Characteristics: Narrow body, spots along dorsal and anal fins with yellow tint on tail fin, dorsal fin, and body
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Lake Tebera Rainbowfish
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The Lake Tebera rainbowfish originates from Papau New Guinea near Lake Tebera. Like Axelrod's rainbowfish, this fish takes their scientific name from aquarist, Herbert Axelrod. They can have a vibrant yellow body with a black stripe along the middle of their sides. Their fins may be tinted red or yellow.
Species Overview
Scientific Name: Melanotaenia herbertaxelrodi
Life Span: 5 years
Length: 4 inches (10 cm)
Physical Characteristics: Wide body, yellow body with black stripe along side
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Sentani Rainbowfish
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Although they may not be considered very "colorful" compared to other rainbowfish, the orange/tan coloration of the Sentani rainbowfish is a bright contrast against the greens of a planted aquarium. Their fins have a mix of blue/green/red pigments that catch the light as they dart around their tank. This is a critically endangered species, so be wary of where you purchase this species and ensure they are captive-bred individuals. The Sentani rainbowfish shares habitat with the red rainbowfish and is commonly mistaken for Chilatherina fasciata.
Species Overview
Scientific Name: Chilatherina sentaniensis
Life Span: 5 years
Length: 4 inches (10 cm)
Physical Characteristics: Wide, tan body with pale stripes and multicolored tail
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Eastern Rainbowfish
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A close relation to the desert rainbowfish, the Eastern rainbowfish has a more orange and gray coloration with iridescent scales. They are best visualized in brightly lit aquariums with lots of plants. This is a larger rainbowfish, but still does best in a small group.
Species Overview
Scientific Name: Melanotaenia splendida spendida
Life Span: 5 years
Length: 6 inches (15 cm)
Physical Characteristics: Wide body, orange and gray with iridescent scales
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Ajamaru Lakes Rainbowfish
The Ajamaru Lakes rainbowfish, or Ajamaru rainbowfish, is from the Ajamaru Lakes in West Papua, Indonesia. Like other rainbowfish, they like being in shoals and in well-planted tanks. These are bi-colored fish, featuring shades of blue and yellow on the body. Also, this species is another that is critically endangered, so care needs to be taken to ensure you purchase these fish from reputable breeders.
Species Overview
Scientific Name: Melanotaenia ajamaruensis
Life Span: 5 years
Length: 4 inches (10 cm)
Physical Characteristics: Wide body, base color of blue to yellow, horizontal dark stripes on the sides
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Aru Rainbowfish
Also known as the painted rainbowfish, the Aru rainbowfish is truly stunning, especially when seen swimming through a planted tank. These fish like to live in aquariums that have rocks and driftwood they can swim around, too. Males feature a blue-gray color with a red spot on the face.
Species Overview
Scientific Name: Melanotaenia picta
Life Span: 5 years
Length: 3.5 inches (9 cm)
Physical Characteristics: Wide body, blue-gray body with yellow hues on the fins and edges of scales
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Barred Rainbowfish
Barred rainbowfish are from New Guinea. They prefer a pH that is 7.1 to 8.1, and water temperatures that are anywhere from 82 to 90 F (28 to 32 C). This species also boasts various body colors, with males being more deeply colored than females. And when males are spawning, the top of their head will be bronze.
Species Overview
Scientific Name: Chilatherina fasciata
Life Span: 8 years
Length: 5 inches (12 cm)
Physical Characteristics: Wide body, various colorations, such as blue-green or brown on top half and yellow to white on the bottom half
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Black Banded Rainbowfish
As the name implies, the black banded rainbowfish has a long black stripe that runs along the middle of the body from the head to the tail. And, like other rainbowfish species, this one is iridescent, so they look brilliant when swimming throughout your aquarium. To mimic their natural habitat, add plants to your tank along with a substrate of fine gravel.
Species Overview
Scientific Name: Melanotaenia nigrans
Life Span: 5 years
Length: 4 inches (10 cm)
Physical Characteristics: Thin, bluish-lavender body with a dark stripe that runs the length of the body
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Bonti Rainbowfish
Bonti rainbowfish are brightly colored and slender, with big eyes. These schooling fish also have beautiful, delicate fins (including two dorsal fins), so they shouldn’t be kept with other fish that might nip at them. They can showcase a variety of hues on their light-colored body and can have yellowish fins that stand out.
Species Overview
Scientific Name: Telmatherina bonti
Life Span: 5 years
Length: 3 inches (8 cm)
Physical Characteristics: Thin body, can have hues of white, green, blue, yellow, and brown
How to Care for Rainbowfish
Whenever you are looking to add fish to your aquarium, ensure that your water quality parameters are correct before you mix different species. Trying to hit a "sweet spot" to accommodate a variety of water quality requirements may not end well. It is best to pick a mix of species that have compatible water requirements rather than mixing by appearance.
In a home aquarium, rainbowfish need well-oxygenated water with a pH level of 6.8 to 7.2, and optimal temperatures varying between 72 to 82 F (22 to 28 C). Provide plenty of aquatic plants to give them hiding places. If properly cared for, rainbowfish can live for five years in aquariums.
What Do Rainbowfish Eat?
Rainbowfish are omnivores, so they eat animals and plants. You can feed them a variety of fish foods and treats that can be purchased at pet stores, such as pellets and flakes as well as frozen, freeze-dried, and live foods.
How Many Rainbowfish Should Be Kept Together?
Most rainbowfishes like to be in a small school, so plan on having at least five to six individuals for the larger species and eight to 10 individuals for the smaller species. Ensure that your aquarium will have enough space for all your fish.
Rainbowfish are generally peaceful community fish, so they can easily be mixed with other tropical community fish, such as tetras, guppies, mollies, and danios—again, provided their water quality requirements are compatible.
Always thoroughly vet any potential vendor to ensure you are buying captive bred fish and are not taking any endangered fish from the wild. Many rainbowfish species are threatened or endangered and need to be purchased from a reliable vendor that sells commercially farmed fish.