Can Peter's Elephantnose Fish and Scat (Brackish) Live Together?

🔴Not Recommended

Peter's Elephantnose Fish and Scat (Brackish) are not recommended as tank mates due to incompatible water types. 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

Scat (Brackish)

Scatophagus argus

🐟Family Group
Peter's Elephantnose Fish
Oddballs
Scat (Brackish)
Oddballs
Temperament
Peter's Elephantnose Fish
Mostly Peaceful (4/10)
Scat (Brackish)
Mostly Peaceful (4/10)
Temperature
✓ Compatible
Peter's Elephantnose Fish
23–28°C
Scat (Brackish)
20–28°C
pH Range
✓ Compatible
Peter's Elephantnose Fish
6–7.5
Scat (Brackish)
7.5–8.5
Hardness (dGH)
✓ Compatible
Peter's Elephantnose Fish
2–15
Scat (Brackish)
12–30
Water Type
✗ No overlap
Peter's Elephantnose Fish
Freshwater Only
Scat (Brackish)
Brackish Required
Flow Preference
✓ Compatible
Peter's Elephantnose Fish
Moderate
Scat (Brackish)
High
Min Tank Volume
Combined: 540 L
Peter's Elephantnose Fish
200 L
Scat (Brackish)
450 L
Swimming Level
Shared: 2 zones
Peter's Elephantnose Fish
BottomMiddle
Scat (Brackish)
MiddleBottom
🏷️Behavior Tags
Peter's Elephantnose Fish
NocturnalShy / Slow Moving (Easily Stressed)Jumper (Lid Required)Aggressive to same species/look-alikes
Scat (Brackish)
Plant DestroyerHyperactive / Fast SwimmerAggressive Eater (Starves shy fish)Fin Nipper

Behaviour & Temperament

Both Peter's Elephantnose Fish and Scat (Brackish) are generally mild-mannered species with an aggression score of 4/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Peter's Elephantnose Fish and Scat (Brackish) 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. Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

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 23°C and 28°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 12–15 dGH. Regular testing will ensure conditions stay within this range.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together.

Tank Setup

To house Peter's Elephantnose Fish and Scat (Brackish) together, plan for an aquarium of at least 540 litres with a minimum length of 150 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

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), Established Algae (Otocinclus). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Scat (Brackish) is a plant destroyer, which conflicts with Peter's Elephantnose Fish's requirement for live plants. Compromise where possible or prioritise the more critical need.

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

Diet & Feeding

Feeding time deserves special attention with this pairing. Scat (Brackish) is an aggressive eater that may prevent Peter's Elephantnose Fish from getting enough food.

Because Scat (Brackish) is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Peter's Elephantnose Fish receives an adequate share.

Frequently Asked Questions

Can Peter's Elephantnose Fish and Scat (Brackish) live together?

No. This combination is not recommended. Key incompatibilities — such as different water type needs — make cohabitation unsafe.

What size tank do Peter's Elephantnose Fish and Scat (Brackish) need?

A minimum of 540 litres (tank length at least 150 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 Scat (Brackish) together?

Keep the aquarium between 23°C and 28°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Peter's Elephantnose Fish or Scat (Brackish) aggressive?

Peter's Elephantnose Fish is generally mild-mannered (4/10) and Scat (Brackish) is generally mild-mannered (4/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Peter's Elephantnose Fish and Scat (Brackish) need?

Both species overlap in the 7.5–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Will Scat (Brackish) nip Peter's Elephantnose Fish's fins?

Scat (Brackish) is a known fin nipper. If Peter's Elephantnose Fish has long or flowing fins, there is a real risk of fin damage. Keeping Scat (Brackish) in a larger group can help redirect nipping behaviour toward conspecifics.

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.


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