Can Least Killifish (Heterandria) and Peter's Elephantnose Fish Live Together?

🟢Ideal Tank Mates

Yes, Least Killifish (Heterandria) and Peter's Elephantnose Fish are ideal tank mates. Both species share compatible water parameters and peaceful temperaments, making them well-suited for a community aquarium. A minimum tank size of 240 litres is recommended.


At a Glance

Least Killifish (Heterandria)

Heterandria formosa

Peter's Elephantnose Fish

Gnathonemus petersii

🐠Family Group
Least Killifish (Heterandria)
Livebearers
Peter's Elephantnose Fish
Oddballs
Temperament
Least Killifish (Heterandria)
Peaceful (1/10)
Peter's Elephantnose Fish
Mostly Peaceful (4/10)
Temperature
✓ Compatible
Least Killifish (Heterandria)
18–27°C
Peter's Elephantnose Fish
23–28°C
pH Range
✓ Compatible
Least Killifish (Heterandria)
7–8
Peter's Elephantnose Fish
6–7.5
Hardness (dGH)
✓ Compatible
Least Killifish (Heterandria)
5–20
Peter's Elephantnose Fish
2–15
Water Type
✓ Compatible
Least Killifish (Heterandria)
Brackish Tolerant
Peter's Elephantnose Fish
Freshwater Only
Flow Preference
✓ Compatible
Least Killifish (Heterandria)
Low
Peter's Elephantnose Fish
Moderate
Min Tank Volume
Combined: 240 L
Least Killifish (Heterandria)
19 L
Peter's Elephantnose Fish
200 L
Swimming Level
Shared: 2 zones
Least Killifish (Heterandria)
TopMiddleBottom
Peter's Elephantnose Fish
BottomMiddle
🏷️Behavior Tags
Least Killifish (Heterandria)
Nano / Bite-sized (Predation Risk)Shy / Slow Moving (Easily Stressed)
Peter's Elephantnose Fish
NocturnalShy / Slow Moving (Easily Stressed)Jumper (Lid Required)Aggressive to same species/look-alikes

Behaviour & Temperament

Least Killifish (Heterandria) is a peaceful species (1/10), while Peter's Elephantnose Fish is generally mild-mannered (4/10). This modest difference means Peter's Elephantnose Fish may occasionally assert dominance over Least Killifish (Heterandria).

Least Killifish (Heterandria) and Peter's Elephantnose Fish 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.

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 27°C. Aim for the midpoint of this range (around 25.0°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 Least Killifish (Heterandria) 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.

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, Plants - Floating, 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 low (still water) water movement, so a standard filtration setup rated for the tank volume should suffice.

Find the right tank equipment

Browse tanks, décor, and equipment suited for this setup.

Frequently Asked Questions

Can Least Killifish (Heterandria) and Peter's Elephantnose Fish live together?

Yes. Least Killifish (Heterandria) and Peter's Elephantnose Fish are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Least Killifish (Heterandria) 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 Least Killifish (Heterandria) and Peter's Elephantnose Fish together?

Keep the aquarium between 23°C and 27°C. A target of around 25.0°C sits comfortably within both species' preferred ranges.

Are Least Killifish (Heterandria) or Peter's Elephantnose Fish aggressive?

Least Killifish (Heterandria) is peaceful (1/10) and Peter's Elephantnose Fish is generally mild-mannered (4/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Least Killifish (Heterandria) 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.


Related Comparisons

Least Killifish (Heterandria) & Guppy

·

🟡Possible with Caution
Least Killifish (Heterandria): PeacefulGuppy: Peaceful

Least Killifish (Heterandria) & Molly (Sailfin/Black/Dalmatian)

·

🟡Possible with Caution
Least Killifish (Heterandria): PeacefulMolly (Sailfin/Black/Dalmatian): Peaceful

Least Killifish (Heterandria) & Platy

·

🟡Possible with Caution
Least Killifish (Heterandria): PeacefulPlaty: Peaceful

Least Killifish (Heterandria) & Endler's Livebearer

·

🟡Possible with Caution
Least Killifish (Heterandria): PeacefulEndler's Livebearer: Peaceful

Least Killifish (Heterandria) & Apple Snail

·

🟡Possible with Caution
Least Killifish (Heterandria): PeacefulApple Snail: Peaceful

Least Killifish (Heterandria) & Bladder Snail (Pest Snail)

·

🟡Possible with Caution
Least Killifish (Heterandria): PeacefulBladder Snail (Pest Snail): Peaceful

Peter's Elephantnose Fish & Black Ghost Knifefish

·

🟡Possible with Caution
Peter's Elephantnose Fish: PeacefulBlack Ghost Knifefish: Peaceful

Peter's Elephantnose Fish & Indonesian Datnoid (Tiger Fish)

·

🟡Possible with Caution
Peter's Elephantnose Fish: PeacefulIndonesian Datnoid (Tiger Fish): Peaceful

Peter's Elephantnose Fish & Fire Eel

·

🟢Ideal Tank Mates
Peter's Elephantnose Fish: PeacefulFire Eel: Peaceful

Peter's Elephantnose Fish & Reedfish (Ropefish)

·

🔴Not Recommended
Peter's Elephantnose Fish: PeacefulReedfish (Ropefish): Peaceful

Peter's Elephantnose Fish & Tire Track Eel

·

🟡Possible with Caution
Peter's Elephantnose Fish: PeacefulTire Track Eel: Peaceful

Peter's Elephantnose Fish & Clown Knifefish

·

🟡Possible with Caution
Peter's Elephantnose Fish: PeacefulClown Knifefish: Peaceful