Celestial Pearl Danio Care (2026)

Species guide

Celestial Pearl Danio (CPD) Care Guide

Fish

Celestial pearl danios (Danio margaritatus, CPD / galaxy rasbora) are tiny spotted schooling fish. They are shy, cooler-water, and plant-dependent. They are not guppies, not chili rasboras, and not a 5-gal ‘desktop mascot’ of three fish.

Celestial pearl danio (Danio margaritatus)

Nano school
Cooler water
Plant cover
Not a guppy

Quick facts

Temp	22–26 °C — skip hot 28 °C discus rooms
pH / GH	Soft–moderate, pH ~6.5–7.5; stability > blackwater cosplay
Volume	10+ gal / 40 L; 20 gal is easier for a full school
School	8–10+; pairs hide and fade
Size	~2–2.5 cm — small mouths, small meals
Cover	Moss, fern, floaters; they spawn in plants
Flow	Gentle; they are not hillstream danios
Diet	Micro pellets / baby brine / crushed flakes — not large cichlid pellets

Overview

CPDs look like jewelry and act like prey. A bare nano makes them invisible. Guppies want harder, warmer water and will outcompete them. Chili rasboras are even smaller blackwater fish — similar vibe, different genus.

Plants: Java moss · Java fern · Monte Carlo if light allows. Cycle: fishless. Nano budget: $50 nano. Schooling contrast: neons · cardinals.

How to keep them

Step 1 School first, décor second
Eight CPDs in moss beat three CPDs in a ‘scaped’ empty midwater. They color up in groups.
Step 2 Keep it cooler than a betta tank
22–25 °C is the sweet spot. Hot water + shy fish = hiding and velvet risk.
Step 3 Plant a spawning thicket
Java moss piles are where they scatter eggs. You will get fry only if adults cannot eat every egg — dense moss helps.
Step 4 Feed tiny, often
Micro foods 1–2×/day. Large pellets rot while they ignore them.
Step 5 Lid + gentle filter
They can jump. Sponge filter or baffled HOB. Strong flow pins them to glass.

Common problems

Always hiding, no spots visible

Why: Too few fish or no cover / too bright.

Fix: Add more CPD + moss + dimmer photoperiod.

Ich or velvet after import

Why: Stress + warm dirty water.

Fix: Quarantine; stable temp; planted-safe treatment.

Males chasing constantly, deaths

Why: Too many males, too little moss.

Fix: Rebalance sexes if you can; add thickets.

Guppies or tetras steal all food

Why: Mouth size mismatch.

Fix: Feed micro foods after lights-down; or separate tanks.

Tank mates

Good: cherry shrimp (some shrimplet loss), small snails, maybe pygmy corys in 20 gal.
OK: chili rasboras in 20+ if you keep both well-fed and planted.
Bad: bettas, large tetras, guppies in tiny tanks, anything that hunts nano fish.
Crystal shrimp: parameter fight (CRS cooler/softer/RO). Do not force both in tap.