Spotted Rainbowfish
Glossolepis maculosus
A small, beautiful rainbowfish endemic to the Markham and Ramu river systems of Papua New Guinea. Unusually small for a Glossolepis species, it features a greenish-bronze body adorned with up to eight distinct black spots along its sides. They are peaceful, active schooling fish that thrive in densely planted aquariums with slow-moving water.
Spotted Rainbowfish At a Glance
Spotted Rainbowfish Tank Requirements
Will Spotted Rainbowfish fit in your tank?
Care guides tell you what Spotted Rainbowfish needs, the next question is whether your tank can safely provide it. Test Spotted Rainbowfish against your tank size, maintenance needs, and the fish you already keep before you buy.
Spotted Rainbowfish Water Parameters
Spotted Rainbowfish Temperament & Compatibility
Spotted Rainbowfish Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Male
Males display brighter yellow-greenish colors on their sides and have slightly deeper bodies and longer fins than females. During courtship, they will actively display and chase females. Best kept with a higher ratio of females.
Differs in 1 trait from base species
Also known as: Male Spotted Rainbowfish, Standard
Female
Females are slightly smaller, have a more slender profile, and possess less vibrant coloration than males. They need plenty of hiding spots among plants to retreat from overly amorous males.
Differs in 2 traits from base species
Also known as: Female Spotted Rainbowfish
Spotted Rainbowfish Care Guide Summary
The Spotted Rainbowfish, scientifically known as Glossolepis maculosus, belongs to the Rainbowfish family group. Adults reach a maximum size of approximately 6 cm and have a fusiform body shape with a moderate growth rate. Classified as peaceful, this species primarily occupies the mid-level and surface zones of the aquarium and produces a low level of biological waste.
To thrive, the Spotted Rainbowfish requires a freshwater only aquarium with a minimum volume of 60 litres and a tank length of at least 60 cm. Water temperature should be maintained between 23°C and 28°C, with a pH range of 7–8 and a general hardness of 8–15 dGH. A low water flow is preferred.
The Spotted Rainbowfish is a rewarding species to keep, provided its core environmental needs are met. This species is available in 2 varieties: Male and Female. Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Spotted Rainbowfish Habitat Setup
When setting up an aquarium for the Spotted Rainbowfish, a low water flow best suits their natural preferences. Because this species occupies the mid-level and surface zones, the aquarium layout should prioritise adequate surface area with floating cover to make them feel secure near the waterline and open swimming space in the centre of the tank for free movement. Useful additions include dense planting to provide cover, break sightlines, and reduce stress. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.
Spotted Rainbowfish Compatibility Notes
Classified as peaceful, the Spotted Rainbowfish is a schooling species that feels most secure in a sizeable group, where natural shoaling behaviour reduces stress and brings out their best colours. When choosing tankmates, their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the mid-level and surface zones can help reduce competition and territorial overlap.
Who Spotted Rainbowfish Is Actually For
Spotted Rainbowfish is best for a fishkeeper who wants a species that can settle into a calmer community setup and can provide a keeper who can commit to a proper group of at least 6. It makes the most sense for a hobbyist who will actually build around its needs, especially plants.
The most common mistake is buying Spotted Rainbowfish for looks first and only later discovering how its adult size, behavior, or bioload changes the whole tank plan. Another frequent problem is underestimating its social needs. A token pair or trio often behaves very differently from a real group.
Spotted Rainbowfish Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Spotted Rainbowfish.
20 Gallon High
20 Gallon Long
29 Gallon Standard
30 Gallon Breeder
36 Gallon Bowfront
40 Gallon Breeder
Show 19 more tank sizes
Frequently Asked Questions About Spotted Rainbowfish
How big does Spotted Rainbowfish get?
Spotted Rainbowfish (Glossolepis maculosus) typically reaches a maximum adult size of approximately 6 cm. They have a fusiform body shape and a moderate growth rate.
What tank size does Spotted Rainbowfish need?
A minimum aquarium volume of 60 litres and a tank length of at least 60 cm are recommended for Spotted Rainbowfish. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Spotted Rainbowfish need?
Spotted Rainbowfish thrives in freshwater only conditions with a temperature range of 23–28°C, a pH between 7 and 8, and a general hardness of 8–15 dGH. A low water flow is preferred.
Is Spotted Rainbowfish peaceful or aggressive?
Spotted Rainbowfish is classified as peaceful with an aggression score of 2 out of 10. They are generally well-suited to peaceful community tanks.
How many Spotted Rainbowfish should be kept together?
Spotted Rainbowfish is a schooling species and should be kept in groups of at least 6. Larger groups help distribute aggression and encourage natural schooling behaviour.
Does Spotted Rainbowfish have any special tank requirements?
Yes. Spotted Rainbowfish benefits from plants - densely covered in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Spotted Rainbowfish need a lid on the tank?
Yes. Spotted Rainbowfish is a known jumper, and a tight-fitting lid or cover is essential to prevent escape. Even a small gap can be enough for a determined fish to leap out.
Useful setup supplies
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Guidarium Editorial Desk
Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.
- Last reviewed
- May 11, 2026
- Last updated
- May 11, 2026
- Issues or corrections?
- Contact the editorial team
Top Tank Mates for Spotted Rainbowfish
These fish are strong compatibility matches for Spotted Rainbowfish based on water preferences, temperament, adult size, and tank behavior.
Trapdoor Snail
Cipangopaludina chinensis
Ideal Tank MatesReticulated Stingray (Teacup Ray)
Potamotrygon orbignyi
Ideal Tank MatesTandanus Catfish
Tandanus tandanus
Ideal Tank MatesSkunk Cory
Corydoras arcuatus
Ideal Tank MatesSan Juan Cory
Corydoras bilineatus
Ideal Tank MatesPetricola Catfish
Synodontis petricola
Ideal Tank MatesPlants That Suit Spotted Rainbowfish
These plants pair well with Spotted Rainbowfish based on shared water preferences, layout fit, and how likely they are to hold up in the same aquarium.
Amazon Frogbit
Limnobium laevigatum
Asian Watergrass
Hygroryza aristata
Asian Watermoss
Salvinia cucullata
Beckett's Water Trumpet
Cryptocoryne beckettii
Broad-leaved Crypt
Cryptocoryne pontederiifolia
Carolina Fanwort
Cabomba caroliniana
Fish Similar to Spotted Rainbowfish
MacCulloch's Rainbowfish (Dwarf Rainbowfish)
Melanotaenia maccullochi
A smaller, peaceful species of rainbowfish native to Australia and Papua New Guinea. They feature striking silver/yellow bodies with horizontal red, brown, or orange stripes. Unlike larger Melanotaenia species, their smaller size makes them suitable for medium aquariums. They are highly active schooling fish that require open swimming space and display their best colors in the morning.
Ogilby's Rainbowfish
Melanotaenia ogilbyi
A rare and stunning schooling fish endemic to the Lorentz River system in West Papua. Belonging to the 'maccullochi' species group, they are relatively small for rainbowfish. They feature a distinct dark mid-lateral stripe and striking horizontal red/orange stripes between their scales. They are incredibly active, peaceful, and thrive in groups where males will 'flash' vibrant colors during morning spawning displays.
Ramu Rainbowfish
Glossolepis ramuensis
The Ramu Rainbowfish is a beautiful, active schooling fish native to the Ramu River basin in Papua New Guinea. In the wild, they inhabit clear creeks with rocky and gravel bottoms. They are fast, active swimmers requiring plenty of lateral swimming space. Males develop stunning greenish-purple backs with orange stripes, while females remain silvery. Best kept in groups with a higher ratio of females to males.
Kabia rainbowfish
Glossolepis kabia
A rare and active schooling fish endemic to the Sepik and Ramu river basins of Papua New Guinea. Known for their silvery-green to blue iridescence, they inhabit slow-moving rivers, swampy lagoons, and oxbow lakes. Like most rainbowfish, they require ample horizontal swimming space and thrive in planted aquariums with stable, clean water.
Fly River Rainbowfish
Melanotaenia sexlineata
A brilliantly colored, peaceful dwarf rainbowfish native to the upper Fly River system in Papua New Guinea. Recognized by its golden-turquoise sheen, distinctive horizontal stripes, and sometimes bright pink lips. Being an exceptionally active shoaling species, they require significant lateral swimming space despite their small size.
Bulolo Rainbowfish
Chilatherina bulolo
A rare and highly active rainbowfish native to the fast-flowing mountain streams and white-water rapids of the Markham and Ramu river systems in Papua New Guinea. They possess a silvery body with a distinct black streak on the upper and lower edges of the caudal fin. Because of their specialized natural habitat, they require highly oxygenated, fast-flowing water and alkaline conditions to thrive in an aquarium.