Can Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red) Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 11, 2026
Not Recommended

Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red) are not recommended as tank mates due to conflicting pH requirements. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Celestial Pearl Danio (Galaxy Rasbora)

Danio margaritatus

Red Peacock (Ruby Red)

Aulonocara sp. 'Rubescens'

🐠Family Group
Celestial Pearl Danio (Galaxy Rasbora)
Cyprinids
Red Peacock (Ruby Red)
Cichlids - African
Temperament
Celestial Pearl Danio (Galaxy Rasbora)
Peaceful (2/10)
Red Peacock (Ruby Red)
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Celestial Pearl Danio (Galaxy Rasbora)
20–26°C
Red Peacock (Ruby Red)
24–28°C
pH Range
✗ No overlap
Celestial Pearl Danio (Galaxy Rasbora)
6.5–7.5
Red Peacock (Ruby Red)
7.8–8.6
Hardness (dGH)
✓ Compatible
Celestial Pearl Danio (Galaxy Rasbora)
5–15
Red Peacock (Ruby Red)
10–25
Water Type
✓ Compatible
Celestial Pearl Danio (Galaxy Rasbora)
Freshwater Only
Red Peacock (Ruby Red)
Freshwater Only
Flow Preference
✓ Compatible
Celestial Pearl Danio (Galaxy Rasbora)
Low
Red Peacock (Ruby Red)
Moderate
Min Tank Volume
Combined: 208 L
Celestial Pearl Danio (Galaxy Rasbora)
38 L
Red Peacock (Ruby Red)
208 L
Swimming Level
Shared: 2 zones
Celestial Pearl Danio (Galaxy Rasbora)
MiddleBottom
Red Peacock (Ruby Red)
MiddleBottom
🏷️Behavior Tags
Celestial Pearl Danio (Galaxy Rasbora)
Nano / Bite-sized (Predation Risk)Shy / Slow Moving (Easily Stressed)
Red Peacock (Ruby Red)
Digger (Disturbs Substrate)Fry PredatorTerritorial (Defends specific area)Aggressive to same species/look-alikesHyperactive / Fast Swimmer
Stocking calculator

Can your tank handle Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red)?

Compatibility is only part of the answer. Test both fish with your real tank size, current stock, and maintenance needs to see if you have enough space and a safe stocking level before you add them.

Celestial Pearl Danio (Galaxy Rasbora)
Red Peacock (Ruby Red)
Test both in my tank

Behaviour & Temperament

Celestial Pearl Danio (Galaxy Rasbora) is a peaceful species (2/10), while Red Peacock (Ruby Red) is moderately assertive (6/10). This notable difference means Red Peacock (Ruby Red) may occasionally assert dominance over Celestial Pearl Danio (Galaxy Rasbora).

Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red) both frequent the Middle (Open Water) and Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Water Parameters

The safe temperature window for both species falls between 24°C and 26°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

The pH requirements of Celestial Pearl Danio (Galaxy Rasbora) (6.5–7.5) and Red Peacock (Ruby Red) (7.8–8.6) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 10–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red) together, plan for an aquarium of at least 208 litres with a minimum length of 120 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.

Specific environmental needs for this combination include: Plants - Densely covered, Sand (Sifters), Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Both species do well with low (still water) water movement, so a standard filtration setup rated for the tank volume should suffice.

Why This Pairing Usually Fails in Practice

Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red) are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red).

Show 5 more tank sizes

Frequently Asked Questions

Can Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red) live together?

No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.

What size tank do Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red) need?

A minimum of 208 litres (tank length at least 120 cm) is recommended. This provides enough space for both species to establish their own areas and reduces the likelihood of territorial disputes.

What water temperature is best for Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red) together?

Keep the aquarium between 24°C and 26°C. A target of around 25.0°C sits comfortably within both species' preferred ranges.

Are Celestial Pearl Danio (Galaxy Rasbora) or Red Peacock (Ruby Red) aggressive?

Celestial Pearl Danio (Galaxy Rasbora) is peaceful (2/10) and Red Peacock (Ruby Red) is moderately assertive (6/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Celestial Pearl Danio (Galaxy Rasbora) and Red Peacock (Ruby Red) need?

Their pH requirements do not overlap. Celestial Pearl Danio (Galaxy Rasbora) prefers 6.5–7.5, while Red Peacock (Ruby Red) needs 7.8–8.6. This makes them incompatible in the same water chemistry.

How do I manage Red Peacock (Ruby Red)'s territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Red Peacock (Ruby Red) space to claim a territory without encroaching on the other fish's area. Adding décor that divides the tank into distinct zones works especially well.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
May 11, 2026
Last updated
May 11, 2026
Issues or corrections?
Contact the editorial team

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