Can Goldfish (Comet / Common) and Red Hump Eartheater Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 11, 2026
Possible with Caution

Keeping Goldfish (Comet / Common) and Red Hump Eartheater together is possible but requires caution due to differing aggression levels. Provide a spacious tank of at least 281 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Goldfish (Comet / Common)

Carassius auratus

Red Hump Eartheater

Geophagus steindachneri

🐠Family Group
Goldfish (Comet / Common)
Goldfish & Koi
Red Hump Eartheater
Cichlids - South American
Temperament
Goldfish (Comet / Common)
Peaceful (1/10)
Red Hump Eartheater
Semi-Aggressive (5/10)
Temperature
✓ Compatible
Goldfish (Comet / Common)
10–24°C
Red Hump Eartheater
24–29°C
pH Range
✓ Compatible
Goldfish (Comet / Common)
6.5–8
Red Hump Eartheater
6.5–7.5
Hardness (dGH)
✓ Compatible
Goldfish (Comet / Common)
5–20
Red Hump Eartheater
4–15
Water Type
✓ Compatible
Goldfish (Comet / Common)
Freshwater Only
Red Hump Eartheater
Freshwater Only
Flow Preference
✓ Compatible
Goldfish (Comet / Common)
Moderate
Red Hump Eartheater
Moderate
Min Tank Volume
Combined: 281 L
Goldfish (Comet / Common)
200 L
Red Hump Eartheater
200 L
Swimming Level
Shared: 2 zones
Goldfish (Comet / Common)
TopMiddleBottom
Red Hump Eartheater
BottomMiddle
🏷️Behavior Tags
Goldfish (Comet / Common)
Plant DestroyerDigger (Disturbs Substrate)Aggressive Eater (Starves shy fish)Hyperactive / Fast Swimmer
Red Hump Eartheater
Digger (Disturbs Substrate)Territorial (Defends specific area)
Stocking calculator

Can your tank handle Goldfish (Comet / Common) and Red Hump Eartheater?

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.

Goldfish (Comet / Common)
Red Hump Eartheater
Test both in my tank

Behaviour & Temperament

Goldfish (Comet / Common) is a peaceful species (1/10), while Red Hump Eartheater is moderately assertive (5/10). This notable difference means Red Hump Eartheater may occasionally assert dominance over Goldfish (Comet / Common).

Goldfish (Comet / Common) and Red Hump Eartheater 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.

To improve the chances of a peaceful coexistence in this community tank: Provide a significantly larger tank (at least 50% more volume than the minimum) to allow both Goldfish (Comet / Common) and Red Hump Eartheater to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations. 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 24°C. Aim for the midpoint of this range (around 24.0°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 5–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Goldfish (Comet / Common) and Red Hump Eartheater together, plan for an aquarium of at least 281 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.

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: Sand (Sifters), 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.

Why This Pairing Needs Extra Planning in Practice

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Goldfish (Comet / Common) and Red Hump Eartheater need extra room, more cover, and closer observation during the first few weeks so small aggression, feeding, or territory issues do not snowball into a long-term problem.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Goldfish (Comet / Common) and Red Hump Eartheater.

Show 1 more tank size

Frequently Asked Questions

Can Goldfish (Comet / Common) and Red Hump Eartheater live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 281 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Goldfish (Comet / Common) and Red Hump Eartheater need?

A minimum of 281 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 Goldfish (Comet / Common) and Red Hump Eartheater together?

Keep the aquarium between 24°C and 24°C. A target of around 24.0°C sits comfortably within both species' preferred ranges.

Are Goldfish (Comet / Common) or Red Hump Eartheater aggressive?

Goldfish (Comet / Common) is peaceful (1/10) and Red Hump Eartheater is moderately assertive (5/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Goldfish (Comet / Common) and Red Hump Eartheater 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.

How do I manage Red Hump Eartheater's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Red Hump Eartheater 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.

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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