Can Altifrons Eartheater and Koi Live Together?

Ideal Tank Mates

Yes, Altifrons Eartheater and Koi 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 3785 litres is recommended.


At a Glance

Altifrons Eartheater

Geophagus altifrons

Koi

Cyprinus rubrofuscus

🐠Family Group
Altifrons Eartheater
Cichlids - South American
Koi
Goldfish & Koi
Temperament
Altifrons Eartheater
Mostly Peaceful (4/10)
Koi
Peaceful (2/10)
Temperature
✓ Compatible
Altifrons Eartheater
24–30°C
Koi
4–28°C
pH Range
✓ Compatible
Altifrons Eartheater
5–7.5
Koi
6.5–8.5
Hardness (dGH)
✓ Compatible
Altifrons Eartheater
1–10
Koi
4–15
Water Type
✓ Compatible
Altifrons Eartheater
Freshwater Only
Koi
Freshwater Only
Flow Preference
✓ Compatible
Altifrons Eartheater
Moderate
Koi
Moderate
Min Tank Volume
Combined: 3785 L
Altifrons Eartheater
475 L
Koi
3785 L
Swimming Level
Shared: 2 zones
Altifrons Eartheater
BottomMiddle
Koi
TopMiddleBottom
🏷️Behavior Tags
Altifrons Eartheater
Digger (Disturbs Substrate)Plant DestroyerHyperactive / Fast SwimmerShrimp EaterFry Predator
Koi
Hyperactive / Fast SwimmerPlant DestroyerDigger (Disturbs Substrate)Fry PredatorAggressive Eater (Starves shy fish)Jumper (Lid Required)
Stocking calculator

Can your tank handle Altifrons Eartheater and Koi?

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.

Altifrons Eartheater
Koi
Test both in my tank

Behaviour & Temperament

Altifrons Eartheater is a generally mild-mannered species (4/10), while Koi is peaceful (2/10). This modest difference means Altifrons Eartheater may occasionally assert dominance over Koi.

Altifrons Eartheater and Koi 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.

Worth noting: Koi 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.

Both fish can tolerate a pH between 6.5 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 4–10 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Altifrons Eartheater and Koi together, plan for an aquarium of at least 3785 litres with a minimum length of 300 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), Driftwood (Digestion/Hiding), Smooth Gravel (Sensitive Barbels). 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.

Frequently Asked Questions

Can Altifrons Eartheater and Koi live together?

Yes. Altifrons Eartheater and Koi are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Altifrons Eartheater and Koi need?

A minimum of 3785 litres (tank length at least 300 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 Altifrons Eartheater and Koi 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 Altifrons Eartheater or Koi aggressive?

Altifrons Eartheater is generally mild-mannered (4/10) and Koi is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Altifrons Eartheater and Koi need?

Both species overlap in the 6.5–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.


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