Can Forktail Blue-eye and Peter's Elephantnose Fish Live Together?

🟡Possible with Caution

Keeping Forktail Blue-eye and Peter's Elephantnose Fish together is possible but requires caution due to potential behavioral clashes. Provide a spacious tank of at least 240 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Forktail Blue-eye

Pseudomugil furcatus

Peter's Elephantnose Fish

Gnathonemus petersii

🐠Family Group
Forktail Blue-eye
Rainbowfish
Peter's Elephantnose Fish
Oddballs
Temperament
Forktail Blue-eye
Peaceful (2/10)
Peter's Elephantnose Fish
Mostly Peaceful (4/10)
Temperature
✓ Compatible
Forktail Blue-eye
24–28°C
Peter's Elephantnose Fish
23–28°C
pH Range
✓ Compatible
Forktail Blue-eye
7–8
Peter's Elephantnose Fish
6–7.5
Hardness (dGH)
✓ Compatible
Forktail Blue-eye
5–15
Peter's Elephantnose Fish
2–15
Water Type
✓ Compatible
Forktail Blue-eye
Freshwater Only
Peter's Elephantnose Fish
Freshwater Only
Flow Preference
✓ Compatible
Forktail Blue-eye
Moderate
Peter's Elephantnose Fish
Moderate
Min Tank Volume
Combined: 240 L
Forktail Blue-eye
55 L
Peter's Elephantnose Fish
200 L
Swimming Level
Shared: 1 zone
Forktail Blue-eye
TopMiddle
Peter's Elephantnose Fish
BottomMiddle
🏷️Behavior Tags
Forktail Blue-eye
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)
Peter's Elephantnose Fish
NocturnalShy / Slow Moving (Easily Stressed)Jumper (Lid Required)Aggressive to same species/look-alikes

Behaviour & Temperament

Forktail Blue-eye is a peaceful species (2/10), while Peter's Elephantnose Fish is generally mild-mannered (4/10). This modest difference means Peter's Elephantnose Fish may occasionally assert dominance over Forktail Blue-eye.

Forktail Blue-eye and Peter's Elephantnose Fish both frequent the 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, Forktail Blue-eye is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat.

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.

Both fish can tolerate a pH between 7 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 5–15 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Forktail Blue-eye and Peter's Elephantnose Fish together, plan for an aquarium of at least 240 litres with a minimum length of 120 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Plants - Densely covered, 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.

Find the right tank equipment

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Frequently Asked Questions

Can Forktail Blue-eye and Peter's Elephantnose Fish live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 240 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Forktail Blue-eye and Peter's Elephantnose Fish need?

A minimum of 240 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 Forktail Blue-eye and Peter's Elephantnose Fish 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 Forktail Blue-eye or Peter's Elephantnose Fish aggressive?

Forktail Blue-eye is peaceful (2/10) and Peter's Elephantnose Fish is generally mild-mannered (4/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Forktail Blue-eye and Peter's Elephantnose Fish need?

Both species overlap in the 7–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

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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