---

title: "Celestial Pearl Danio: The Complete Nano Care & Breeding Guide" description: "The definitive celestial pearl danio / galaxy rasbora (Danio margaritatus) care guide: nano tank setup, water parameters, shoaling, feeding, daily breeding, and tank mates." slug: celestial-pearl-danio commonName: Celestial Pearl Danio scientificName: Danio margaritatus family: Danionidae order: Cypriniformes difficulty: Beginner minTankSize: 10 temperature: "68–78°F (20–26°C)" ph: "6.5–7.5" hardness: "2–12 dGH" lifespan: "3–5 years" maxSize: "0.9 inches (2.3 cm)" origin: "Myanmar" publishedAt: "2026-06-04"

Celestial Pearl Danio: The Complete Nano Care & Breeding Guide

The celestial pearl danio is one of the most jaw-dropping small fish ever to enter the hobby — a tiny, deep-blue jewel scattered with pearl-white spots and barred with red-orange fins, looking less like a fish than a fragment of a galaxy. Discovered only in 2006 and initially the subject of a collection frenzy, Danio margaritatus (still widely sold as the "galaxy rasbora") is now firmly established as a hardy, peaceful, easily-bred nano fish that's perfect for planted and shrimp-friendly tanks.

This guide is the complete reference: the CPD's biology and discovery story, how to set up its nano tank, what to feed it, its shy-but-rewarding behaviour, its prolific breeding, and which tank mates suit it.

---

Species Overview

The celestial pearl danio (Danio margaritatus), or CPD, was originally described as a rasbora ("galaxy rasbora") before being correctly classified as a danio. It is a true nano fish, reaching only about 2.3 cm (0.9 inches). Its coloration is extraordinary: a deep midnight-blue to teal body scattered with iridescent pearl spots, with red-to-orange fins barred in black. Males are more intensely coloured with stronger red fins; females are a little rounder and slightly more subdued.

The CPD is peaceful, hardy, cool-tolerant, and prolific, making it an excellent nano and shrimp-tank fish despite its small size. It can be a touch shy, doing best in a planted tank with cover and a group, where the males display and harmlessly spar in glorious colour. With good care it lives 3–5 years. Its astonishing looks, small size, peaceful nature, and easy breeding have made it one of the most popular nano fish in the world.

---

Natural History and Origin

Danio margaritatus is native to a small area of the Myanmar highlands, where it lives in shallow, cool, clear, heavily-vegetated spring-fed ponds and pools — densely planted, often sun-dappled but cover-rich waters at moderate elevation, hence its tolerance of cooler temperatures than most tropical fish.

The CPD's discovery in 2006 caused a sensation, and intense initial collection raised conservation concerns about its tiny native range. Fortunately, it proved very easy to breed in captivity, and the trade quickly shifted to tank-bred fish, relieving pressure on wild populations — a conservation success driven by aquaculture. Its natural habitat of cool, clear, densely-planted pools explains its preference for cooler, well-planted, calm aquariums with plenty of cover, where these somewhat shy fish feel secure enough to display.

---

Water Parameters

CPDs are adaptable and notably cool-tolerant, thriving at temperatures most tropical fish would find too cold — making them suitable for unheated or cooler tanks (and good companions for other cool-water nano species). Keep the tank cycled and stable — confirm with the nitrogen cycle tracker and check values with the water parameters reference. A planted, stable nano tank suits them perfectly.

---

Tank Setup Guide

Tank size

A group of 8–10 CPDs is comfortable in a 10-gallon (38-litre) nano tank, making them ideal for small planted setups. A larger tank allows a bigger, more impressive group.

Aquascape — dense planting and cover

CPDs are somewhat shy and need a heavily planted tank with cover to feel secure and display their colour. Use Java moss, fine-leaved plants, broad-leaved plants, driftwood, and floating plants like duckweed, with some open space. The dense planting and subdued light coax these timid fish into the open, where the males show their best colour and spar harmlessly — a sparse, bright tank leaves them hiding and washed-out. This is also exactly the kind of scape dwarf shrimp love, which is why the two are kept together.

Filtration, flow, lighting

Use gentle filtration with low flow — a sponge filter is ideal (and shrimp-safe). Subdued, planted lighting suits them and showcases their galaxy colours. The calm, planted, cool environment mirrors their highland-pool home.

---

Feeding Guide

CPDs are micro-predators with tiny mouths, so foods must be small.

What to feed

• Crushed micro-flake and nano/micro-pellets — sized for tiny mouths.
• Live and frozen baby brine shrimp and small daphnia — relished, excellent for colour and condition.
• Cyclops, microworms, and crushed frozen foods for variety.

How often

Feed two to three small meals daily of appropriately tiny foods. CPDs can be shy, deliberate feeders, so ensure they get their share and aren't outcompeted. A varied diet with small live/frozen foods deepens the males' blue and red. A healthy CPD is vividly coloured and active in a well-planted tank.

---

Behavior and Temperament

Celestial pearl danios are peaceful but somewhat shy, especially when newly added or in sparse, bright tanks. In a densely-planted tank with cover and a group of 8 or more, they grow confident, foraging and displaying in the open. The males are the show: they perform constant displays and harmless sparring, flaring their red fins and intensifying their colour to impress females and rivals — a beautiful, non-damaging dynamic best seen in a group with several males and more females.

They are completely peaceful toward other species and, thanks to their tiny size and gentle mouths, are largely shrimp-safe (adults won't harm adult shrimp, though they may eat newborn shrimplets). Their shyness means they do best with calm tank mates in a planted tank; bold or boisterous companions keep them hidden. Given the right setup, CPDs are confident, dazzling, and endlessly watchable.

---

Compatibility

CPDs are superb peaceful nano fish, ideal for planted and shrimp tanks with calm companions.

Good tank mates: ember tetra, cherry shrimp and other dwarf shrimp, neon tetra, harlequin rasbora, pygmy/small corydoras, otocinclus, white cloud minnow (a great cool-water companion), and honey gourami.

Cautions:

• Any fish large enough to eat them — CPDs are tiny.
• Boisterous or aggressive fish — keep the shy CPDs hidden.
• Fast greedy feeders — outcompete the small, deliberate CPDs.

A CPD group with ember tetras, pygmy corydoras, and a cherry shrimp colony in a planted nano tank is a stunning, harmonious community. Use the compatibility checker to plan.

---

Breeding Guide

Celestial pearl danios are prolific and easy to breed — a continuous spawner that scatters eggs daily in good conditions, which is exactly why the trade shifted so quickly to tank-bred fish.

Sexing is straightforward: males are more intensely coloured with stronger red-orange fins and a slimmer body; females are rounder with more subdued fins. In a well-fed, planted tank, a group will spawn continuously, the females scattering a few eggs each day among fine-leaved plants and Java moss.

The catch is that adults (and tank mates) eat the eggs and fry, so in a community tank few survive. To raise them, either provide a dense moss thicket that protects fallen eggs and fry, or move eggs/spawning mops to a separate rearing tank. The tiny fry need the smallest first foods — infusoria and then microworms and baby brine shrimp — in clean, stable water. A heavily-mossed, mature tank often yields a steady trickle of surviving fry with no intervention, which is the easiest way to grow your colony.

---

Health and Disease

CPDs are hardy, and most problems are the standard small-fish issues, infrequent with good care.

Ich can follow temperature swings or stress; treat promptly (and gently if shrimp are present). Bacterial and fungal infections follow poor water or stress. As small, sometimes-shy fish, they're sensitive to chronic stress from inadequate cover, too-small a group, or intimidating tank mates, which dulls colour and undermines health. Newly imported or newly added CPDs may be pale and hidden until settled.

Prevention: a stable, cycled, densely-planted, cool-ish tank, a good-sized group, gentle flow, small varied foods, calm tank mates, and quarantine of new arrivals. Given those, the CPD is a hardy, rewarding, dazzling nano fish.

---

Interesting Facts

• A galaxy in a fish. Its deep-blue body scattered with pearl spots and barred red fins genuinely resembles a fragment of a starry sky — hence "galaxy rasbora."
• A 2006 sensation. Discovered only in 2006, it caused a collection frenzy before aquaculture relieved the pressure on its tiny wild range.
• Cool-water jewel. Unusually for such a colourful fish, it tolerates cooler temperatures and suits unheated tanks.
• Rasbora or danio? First described as a rasbora, it's actually a danio (Danio margaritatus) — both names persist in the trade.
• A daily spawner. Well-kept groups scatter a few eggs every day, making them prolific and easy to breed in a mossy tank.

---

Bringing It Together

The celestial pearl danio is one of the most beautiful small fish in the entire hobby — a tiny galaxy of blue, pearl, and red that, kept in a densely-planted, cool, calm nano tank with a good-sized group, rewards you with constant colourful displays and a steady trickle of fry. Give it gentle flow, small varied foods, plenty of cover, and peaceful tank mates — and pair it with ember tetras, pygmy corydoras, and a cherry shrimp colony, or cool-water companions like the white cloud minnow — and it becomes a dazzling, easily-bred nano centerpiece. Its aquaculture success is also a genuine conservation win. Plan the nano build with the AI Tank Blueprint generator and the compatibility checker.