Can Peter's Elephantnose Fish and Red Peacock (Ruby Red) Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 11, 2026
Not Recommended

Peter's Elephantnose Fish 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

Peter's Elephantnose Fish

Gnathonemus petersii

Red Peacock (Ruby Red)

Aulonocara sp. 'Rubescens'

🐠Family Group
Peter's Elephantnose Fish
Oddballs
Red Peacock (Ruby Red)
Cichlids - African
Temperament
Peter's Elephantnose Fish
Mostly Peaceful (4/10)
Red Peacock (Ruby Red)
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Peter's Elephantnose Fish
23–28°C
Red Peacock (Ruby Red)
24–28°C
pH Range
✗ No overlap
Peter's Elephantnose Fish
6–7.5
Red Peacock (Ruby Red)
7.8–8.6
Hardness (dGH)
✓ Compatible
Peter's Elephantnose Fish
2–15
Red Peacock (Ruby Red)
10–25
Water Type
✓ Compatible
Peter's Elephantnose Fish
Freshwater Only
Red Peacock (Ruby Red)
Freshwater Only
Flow Preference
✓ Compatible
Peter's Elephantnose Fish
Moderate
Red Peacock (Ruby Red)
Moderate
Min Tank Volume
Combined: 208 L
Peter's Elephantnose Fish
200 L
Red Peacock (Ruby Red)
208 L
Swimming Level
Shared: 2 zones
Peter's Elephantnose Fish
BottomMiddle
Red Peacock (Ruby Red)
MiddleBottom
🏷️Behavior Tags
Peter's Elephantnose Fish
NocturnalShy / Slow Moving (Easily Stressed)Jumper (Lid Required)Aggressive to same species/look-alikes
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 Peter's Elephantnose Fish 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.

Peter's Elephantnose Fish
Red Peacock (Ruby Red)
Test both in my tank

Behaviour & Temperament

Peter's Elephantnose Fish is a generally mild-mannered species (4/10), while Red Peacock (Ruby Red) is moderately assertive (6/10). This modest difference means Red Peacock (Ruby Red) may occasionally assert dominance over Peter's Elephantnose Fish.

Peter's Elephantnose Fish and Red Peacock (Ruby Red) both frequent the Bottom (Substrate) and Middle (Open Water) 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.

Worth noting: Peter's Elephantnose Fish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Peter's Elephantnose Fish is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

The pH requirements of Peter's Elephantnose Fish (6–7.5) 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 Peter's Elephantnose Fish 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: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Plants - lighly covered, Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

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

Why This Pairing Usually Fails in Practice

Peter's Elephantnose Fish 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 Peter's Elephantnose Fish and Red Peacock (Ruby Red).

Show 5 more tank sizes

Frequently Asked Questions

Can Peter's Elephantnose Fish 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 Peter's Elephantnose Fish 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 Peter's Elephantnose Fish and Red Peacock (Ruby Red) together?

Keep the aquarium between 24°C and 28°C. A target of around 26.0°C sits comfortably within both species' preferred ranges.

Are Peter's Elephantnose Fish or Red Peacock (Ruby Red) aggressive?

Peter's Elephantnose Fish is generally mild-mannered (4/10) and Red Peacock (Ruby Red) is moderately assertive (6/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Peter's Elephantnose Fish and Red Peacock (Ruby Red) need?

Their pH requirements do not overlap. Peter's Elephantnose Fish prefers 6–7.5, 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.

Does Peter's Elephantnose Fish being nocturnal affect compatibility?

Peter's Elephantnose Fish is most active after lights-out, which naturally reduces daytime encounters with its tank mate. This can actually be beneficial, as both fish get undisturbed time to feed and explore. Just ensure food reaches Peter's Elephantnose Fish during evening hours.

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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