Galaxy Rasbora

The fish commonly known as the Galaxy Rasbora is officially named the Celestial Pearl Danio (CPD), with the scientific name Danio margaritatus. It is a stunning, tiny fish perfect for nano and planted tanks.

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Celestial Pearl Danio (Galaxy Rasbora) Care Guide

 

 

Appearance and Behavior

 

The CPD is a vibrant, trout-shaped fish known for its contrasting pattern: a dark blue/black body covered in bright, pearly white/yellow spots (the “galaxy” or “celestial pearls”) and striped red/orange fins.

• Behavior: They are active shoalers that spend time exploring the middle and bottom levels of the tank. Males will often spar or “dance” with each other, flaring their fins to establish dominance and court females.
• Schooling: They do best in groups of at least 8–10 individuals. A larger group increases their confidence and makes them more visible.

 

Tank Requirements and Water Parameters

 

CPDs prefer stable, heavily planted tanks with moderate lighting.

• Minimum Tank Size: 10 gallons is a suitable minimum for a small group (6-10 fish), but a 15–20 gallon long tank is ideal for a larger school.
• Temperature: They prefer slightly cooler temperatures than many tropical fish: 72°–76° F (22°–24° C). They can often be kept in unheated tanks if the room temperature is stable.
• pH Level: Adaptable to a neutral range: 6.5 to 7.5.
• Aquascape: A densely planted tank is essential. Use fine-leaved plants (like Java Moss), wood, and rocks to create many hiding spots. They feel most secure in a lush environment.

 

Diet and Feeding

 

The tiny mouth of the CPD means they require micro-sized food. They are omnivorous.

• Staple Diet: High-quality, finely crushed flakes or micro-pellets.
• Supplementation: A varied diet, rich in protein, is critical for their vibrant colors and health:
  • Frozen or live Baby Brine Shrimp (newly hatched)
  • Frozen Cyclops or Daphnia
  • Microworms
• Feeding Tip: Feed small amounts 2–3 times a day. Since they are mid-to-bottom dwellers and not strong competitors, ensure the food sinks slowly enough for them to catch it before it is swept away.

 

Compatibility

 

CPDs are peaceful and timid. They are easily stressed by larger, boisterous, or aggressive tank mates.

• Good Tank Mates: Other peaceful nano fish like Least Rasboras, Pygmy Corydoras, Otocinclus, and most Dwarf Shrimp (though they may eat shrimplets).
• Avoid: Any large fish, fast-swimming Danios (like Zebra Danios), and Bettas, as the CPDs are easily intimidated or preyed upon.