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Rainbowfish and blue-eyes are a unique group of colorful, community fish that can be found primarily in the freshwater habitats of Papua New Guinea, Indonesia, and Australia. These energetic schooling fish usually hang out in the top half of the fish tank, so make sure to keep a tight aquarium lid to prevent them from jumping out. While males are more vibrant than females, we recommend keeping more females than males to ensure that the boys show off their brightest colors.

Having both sexes also means that you can have fun breeding them at home. Rainbowfish are egg scatterers that will regularly spawn if you give them plenty of good food and clean water. Just add a spawning mop or two into the aquarium for a week, and then either remove the eggs or the entire mop into a separate grow-out container to prevent the adults from predating on their offspring. The smaller blue-eyes tend to be fairly short-lived, so breeding will help keep your colony going. Larger rainbowfish often take longer to mature but are well-worth the effort because of their dazzling appearance. To help you decide which species to start with, let’s talk about 10 different species that are popular in the aquarium hobby and which one is right for you.

Nano Rainbowfish (Smaller Than 2.5 inches or 6 cm)

1. Forktail Rainbowfish

Pseudomugil furcatus

The forktail blue-eye or furcata rainbowfish is a 2-inch (5 cm) beauty known for its brilliant blue eye, yellow-tipped fins that look like little pom-poms, and distinct forked pattern on the tail. As a native of Papua New Guinean rainforests, they enjoy temperatures between 75–80°F (24–27°C), slightly alkaline pH above 7.0, and at least 5° (90 ppm) GH. Because of their active lifestyle, we like to keep them in a 20-gallon tank or bigger with other peaceful community fish like cory catfish, tetras, and rasboras. Read the full care guide for more details.

2. Red Neon Rainbowfish

Pseudomugil luminatus

As one of the newest nano rainbowfish introduced to the aquarium trade, the red neon blue-eye is a highly sought-after commodity. Males have a vibrant red-orange body, iridescent blue eye and line running along its back, and spotting on the fins. At only 1.5 inches (3.8 cm) in length, you could keep a school of 8–10 red neons in a 10-gallon planted aquarium. Their fiery colors look truly stunning when swimming in front of a lush forest of green aquarium plants. They were originally collected from Papua, Indonesia and can be kept in pH of 6.0–7.5 and temperatures between 68–78°F (20–26° C). As a short-lives species, breeding is highly encouraged and can begin as early as 6 months of age.

3. Threadfin or Featherfin Rainbowfish

Iriatherina werneri

One of the deeper-bodied specimens amongst the nano rainbowfish is the 2-inch (5 cm) threadfin rainbowfish. Their common name comes the male’s long, wispy fins and lovely lyretail. Depending on the locale they were found, their coloration can include yellow, black, blue, and even reddish-pink. Getting a mix of both males and females will encourage the fish to show their most vibrant hues. Featherfin rainbows inhabit slow-moving waterways in New Guinea and Australia that are choked with plant life, so they will appreciate a gentle filter, pH between 6.0–7.5, and tropical temperatures of 74–80°F (23–27°C).

4. Gertrude’s Spotted Blue-Eye Rainbowfish

Pseudomugil gertrudae

This 1.25-inch (3 cm) rainbowfish has a striking appearance because of its yellowy body, bright blue eyes, and pale fins speckled with dark spots. Their natural habitats are swampy, vegetation-filled waters in Australia, New Guinea, and the Aru Islands of Indonesia that often have lots of fallen leaves and driftwood. They are surprisingly hardy enough to live in a wide range of parameters, including pH from 5–8, 70–82°F (21–28°C), and soft to hard water. They breed readily to compensate for their short lifespan, so add lots of yarn mops and floating plants to encourage spawning behavior.

5. Celebes Rainbowfish

Marosatherina ladigesi

Similar to the furcata rainbowfish, the celebes rainbow has a yellow fork in its tail, as well as yellow and black fins with a fringe and a neon blue, horizontal stripe down the back half of its body. At 2–2.5 inches (5–6 cm) long, these speedy swimmers would appreciate a 20-gallon long tank or larger that will give them sufficient space to zoom around. As residents of Sulawesi, Indonesia, they come from harder waters with alkaline pH above 7.0 and tropical temperatures between 72–82°F (22–28°C). Like most nano rainbowfish, they are not picky eaters but do prefer tiny foods that can fit in their mouths — such as crushed flakes, nano pellets, baby brine shrimp, daphnia, and Easy Fry and Small Fish Food.

Medium-Sized Rainbowfish (More Than 2.5 inches or 6 cm)

6. Boesemani Rainbowfish

Melanotaenia boesemani

Boeseman’s rainbowfish are probably the most famous rainbowfish that come from the Melanotaeniidae family, which traditionally have more almond-shaped profiles compared to the torpedo-shaped bodies of their smaller cousins. Males can grow to 4 inches (10 cm) long and have an unusual, bicolored body with a shiny blue front and orange back half. Therefore, these lively fish need a fish tank of at least 4 feet (1.2 m) in length with a heater set to 75–82°F (24–28°C). Discovered in the mountains of West Papua, Indonesia, they can easily handle pH of 6–8 and hard water with 8–20° (140–360 ppm) GH. To learn more about this beautiful species, read our complete care article.

7. Dwarf Neon Rainbowfish

Melanotaenia praecox

At 3 inches (8 cm) in length, the praecox rainbowfish is one of the smaller rainbows in the Melanotaeniidae family, which makes it an attractive option for stocking a medium-sized, 29-gallon aquarium. The males have large, iridescent blue scales and red-orange fins, whereas females have a silvery body with yellow fins. While they can handle a broad spectrum of pH and GH, their home in the New Guinea rainforests has harder, alkaline water ranging from 74–80°F (23–27°C). If you have soft water, consider dosing their tank with mineral supplements like Wonder Shell and Seachem Equilibrium to increase the GH. For more info, see the full article on dwarf neons.

8. Turquoise Rainbowfish

Melanotaenia lacustris

The Lake Kutubu rainbowfish or blue rainbowfish displays two colors that are divided by a black horizontal line — vivid, turquoise on top and a silvery-yellow abdomen. Similar to the Boesemani rainbow, they also grow to 4 inches long (10 cm) and would do well in a 4-foot (1.2 m) aquarium or larger. As you may have guessed by their common name, they are found in Lake Kutubu of Papua New Guinea, which has alkaline pH above 7.0 and harder water. Plus, they can handle tropical temperatures from 70–78°F (21–26°C) and get along with other fast-swimming, community species.

9. Red Rainbowfish

Glossolepis incisus

The New Guinea rainbowfish hails from the alkaline, hard waters of Western New Guinea, Indonesia and is famous for its bright red body and scattering of shiny scales along the lateral line. As one of the larger rainbowfish in the fishkeeping hobby, they can reach almost 5 inches (12 cm) in size and also require a 4-foot aquarium at minimum to handle a school of 6 or more. Like most of the other rainbows in the second half of our list, their appetites are hearty but their mouths are relatively small, so feed them a variety of appropriate-sized, meaty foods — such as krill flakes, Vibra Bites, bloodworms, daphnia, and brine shrimp.

10. Lake Tebera Rainbowfish

Melanotaenia herbertaxelrodi

Lake Tebera is surrounded by mountainous jungles in Papua New Guinea, where the waters are alkaline, high in minerals, tropical in temperature (68–79°F or 20–26°C), and full of aquatic plants. While M. herbertaxelrodi is harder to find at pet stores, its golden yellow body, black horizontal stripe, and red-orange fins make it well-worth the search. At 3.5 inches (9 cm) in length, it can live in a 40-gallon breeder aquarium with other energetic tank mates of a similar size. This includes other rainbowfish, loaches, barbs, gouramis, giant danios, bigger livebearers, and peaceful catfish. Given their love for protein, avoid putting them with dwarf shrimp, baby fish, and anything small enough to fit in their mouths.

While Aquarium Co-Op does not ship live fish, you can check out the amazing selection of rainbowfish offered by our preferred online retailers. Enjoy setting up a fun, action-packed aquarium filled with your favorite species of rainbowfish.