The celestial pearl danio — often sold as the “galaxy rasbora” — is one of the most beautiful nano fish in the hobby: a deep blue body scattered with pearl spots and fins edged in orange-red. Only discovered in 2006, it is a peaceful, tiny shoaling fish perfect for a mature planted nano tank, though it is a little shy and best kept away from boisterous company.

Here is how to keep them.

Quick facts

• Adult size: 2–2.5 cm
• Tank size: 40 litres for a group of 8+
• Water: pH 6.5–7.5, soft to medium, 22–26 °C
• Lifespan: 3–5 years
• Temperament: peaceful, shy

Tank setup

CPDs thrive in a heavily planted, mature nano tank with gentle flow and plenty of cover, which coaxes shy fish into the open. A cooler end of the tropical range (22–24 °C) suits them well. Keep them in an established tank — see new tank syndrome.

Shoaling and feeding

Keep at least eight; males display and spar harmlessly, showing their best colour in a group. Their tiny mouths need small foods — crushed micro pellets, powdered flake and frozen baby brine shrimp.

Tank mates

Best with cherry shrimp, ember tetras, small rasboras and nerite snails. Avoid larger or boisterous fish that intimidate these shy jewels.

Frequently asked questions

Is the galaxy rasbora the same as the celestial pearl danio?

Yes — 'galaxy rasbora' is a common trade name for the celestial pearl danio (Danio margaritatus). They are the same fish.

How many celestial pearl danios should I keep?

At least eight. In a group they feel secure, come into the open more, and males display their brightest colours.

Are celestial pearl danios hard to keep?

They are not difficult but are best kept in a mature, planted nano tank with calm tank mates, as they are small and somewhat shy.

---

— Jaqline Smalling, FishForever