Home / Fishes / Carp, barbs, minnows, loaches / Danionidae / Galaxy rasbora
No federal permit to keepGalaxy rasbora
Danio margaritatus
Fishes › Carp, barbs, minnows, loaches (Cypriniformes) › Danionidae (Danios and rasboras)
Danio margaritatus, the celestial pearl danio, often referred to in the aquarium trade as galaxy rasbora or Microrasbora sp. 'Galaxy', is a small freshwater ray-finned fish belonging to the family Danionidae.
Care at a glance
Species-specific aquarium care
- Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 0.8 in / 2.12 cm).
- Water: Freshwater.
- Layout: An open-water swimmer: needs long, open swimming space with few obstacles.
Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.
Care guide
Species care notes
- Tank: a base of at least 18 × 12 in (roughly 11 US gallons); space needed is rated “modest tank”.
- Water: a fairly wide range, from slightly acidic to slightly alkaline, 68–79 °F, pH 6.5–7.5, 5–15 dGH.
- Behaviour: a shoaling fish best kept in a group of six or more; suited to a community tank.
- Difficulty: Easy (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “This timid species should ideally be kept in a heavily-planted set-up, preferably with a dark substrate.”
- Diet: “Likely to feed on small invertebrates, algae and other zooplankton in nature.”
- Tankmates: “Likely to be intimidated or outcompeted for food by larger or more boisterous tankmates, although the presence of similarly-sized, surface-dwelling species seems to help reduce its shyness.”
- Breeding: “Like many small cyprinids this species is an egg-scattering spawner that shows no parental care.”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Danios and rasboras
Applies to most species in this group. Habitat: These Asian fishes occupy habitats ranging from zebra-danio pools and rice paddies to shaded harlequin streams, rocky Devario streams and planted galaxy-rasbora wetlands. [fg159-zebra, fg159-harlequin, fg159-giant, fg159-galaxy]. Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- Use at least 90 × 30 cm (36 × 12 in) for zebra danios.
- Harlequins require at least 60 × 30 cm (24 × 12 in), shaded planted cover and subdued light.
- Devario aequipinnatus needs at least 120 × 45 cm (48 × 18 in), oxygenated water, moderate flow and a tight lid.
- Galaxy rasboras need dense planting and broken sight lines in at least 45 × 30 cm (18 × 12 in), with gentle sponge filtration.
- Match chemistry: harlequins pH 5.0–7.5, 1–12 dGH; galaxy rasboras pH 6.5–7.5, 5–15 dGH.
Climate & lighting
| Water | 64.4–77°F |
Diet
- Quality flakes or granules sized to the fish.
- Live or frozen Daphnia and Artemia.
- Bloodworms for zebra danios, harlequins and Devario.
- Small sinking foods for galaxy rasboras, which rarely feed at the surface.
Social life
- Keep zebra danios and harlequins in groups of at least 8–10. Galaxy males spar: dense cover and larger groups distribute aggression. Active Devario can overwhelm timid feeders.
Health watch
- Pseudoloma microsporidiosis in zebra danios.
- Pleistophora infection and columnaris can produce similar white lesions in zebra danios.
- Nipped fins among rival galaxy males.
Understanding the animal
About this animal
About this animal
This fish is from Myanmar and Northern Thailand (in Salween basin).
Quoted from the Wikipedia article “Danio margaritatus” (CC BY-SA 4.0) 174
In the wild
In the wild
From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1
| Where it lives | Lives in freshwater, in mangroves. Inhabits small and shallow ponds, at most 30 cm deep and maintained by seepage or springs. The water is clear unless roiled with water temperatures of 22-24°C in January 2007. The ponds have luxuriant submerged aquatic vegetation mainly one or two species of Elodea or Anacharis (Hydrocharitaceae). Present terrestrial vegetation is open grassland. Three other species were collected in the ponds, a Microrasbora similar to M. rubescens; a small species of Yunnanilus; and a piscivorous snakehead, Channa harbourtbutleri. |
| Water it lives in | Freshwater, depth 0–1 m. |
| Climate | Tropical climate. |
From the sources
From the sources
Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.
| Overview | Danio margaritatus, the celestial pearl danio, often referred to in the aquarium trade as galaxy rasbora or Microrasbora sp. 'Galaxy, is a small freshwater ray-finned fish belonging to the family Danionidae. This fish is from Myanmar and Northern Thailand (in Salween basin). It has so far been found only in a very small area near Hopong east of Inle Lake, at an elevation of over 1,000 m (3,400 ft). Its habitat is part of the Salween basin, namely the Nam Lang and Nam Pawn Rivers. — Wikipedia (community-edited) |
| Where it lives | Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase |
| Reproduction | The spawning behavior has significant consequences for captive breeding (see below). The celestial pearl danio appears to be adapted to somewhat ephemeral habitats. It does not have a dedicated spawning season, nor do the females lay continuously. — Wikipedia (community-edited) |
| Appearance and size | This is a small, plump danionin with a markedly blunt snout, measuring 2–2.5 cm standard length,a few individuals are able to reach 3 cm. The body is about three times as long as it is high. In general shape, it resembles Danio erythromicron more than any other known species. — Wikipedia (community-edited) |
| Biology | Inhabits small and shallow ponds, at most 30 cm deep and maintained by seepage or springs. The water is clear unless roiled with water temperatures of 22-24°C in January 2007. The ponds have luxuriant submerged aquatic vegetation mainly one or two species of Elodea or Anacharis (Hydrocharitaceae). — FishBase |
| History and naming | Initially, the celestial pearl danio was assumed to be a member of the genus Microrasbora, due to its similarity to "Microrasbora" erythromicron. Less than a year after the discovery of the celestial pearl danio, it was scientifically described and given the genus name Celestichthys. — Wikipedia (community-edited) |
| Conservation | Within six months of its appearance in the aquarium trade, the species was falsely reported as having become so rare, collectors were obtaining only a "few dozen fish per day". Initially, only a small number of aquarists managed to breed the fish successfully, while nearly all the fish offered for sale were wild-caught. — Wikipedia (community-edited) |
Data and studies
The numbers
The numbers
Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.
Adult length
Maximum recorded length. Measured as standard length (snout to the base of the tail, not counting the tail fin). Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates; aim for the middle.
pH
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 18 × 12 in (about 11 US gallons).
Sources for this sheet
- FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
- Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
- Seriously Fish: Zebra danio (Danio / Brachydanio rerio) Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Trigonostigma heteromorpha Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Devario aequipinnatus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Danio / Celestichthys margaritatus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
- iNaturalist (captive observations) Community referenceCommunity observation platform run by the California Academy of Sciences and National Geographic; observations marked captive show animals living in homes, zoos and aquariums.
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