Can Oscar and Sunset Hap Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 4, 2026
Not Recommended

Oscar and Sunset Hap are not recommended as tank mates due to conflicting pH requirements. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Oscar

Astronotus ocellatus

Sunset Hap

Dimidiochromis strigatus

🐠Family Group
Oscar
Cichlids - South American
Sunset Hap
Cichlids - African
Temperament
Oscar
Aggressive (7/10)
Sunset Hap
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Oscar
23–27°C
Sunset Hap
24–28°C
pH Range
✗ No overlap
Oscar
6–7.5
Sunset Hap
7.6–8.6
Hardness (dGH)
✓ Compatible
Oscar
5–15
Sunset Hap
10–25
Water Type
✓ Compatible
Oscar
Freshwater Only
Sunset Hap
Freshwater Only
Flow Preference
✓ Compatible
Oscar
Moderate
Sunset Hap
Moderate
Min Tank Volume
Combined: 458 L
Oscar
280 L
Sunset Hap
400 L
Swimming Level
Shared: 2 zones
Oscar
MiddleBottom
Sunset Hap
MiddleBottom
🏷️Behavior Tags
Oscar
Piscivore (Eats small/nano fish)Digger (Disturbs Substrate)Plant DestroyerTerritorial (Defends specific area)Generally AggressiveHyperactive / Fast Swimmer
Sunset Hap
Piscivore (Eats small/nano fish)Aggressive to same species/look-alikesHyperactive / Fast SwimmerTerritorial (Defends specific area)
Stocking calculator

Can your tank handle Oscar and Sunset Hap?

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.

Oscar
Sunset Hap
Test both in my tank

Behaviour & Temperament

Oscar is a semi-aggressive species (7/10), while Sunset Hap is moderately assertive (6/10). This modest difference means Oscar may occasionally assert dominance over Sunset Hap.

Oscar and Sunset Hap 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.

Additional behavioural considerations to keep in mind: Two territorial species may clash over territory, especially in smaller tanks.

Water Parameters

The safe temperature window for both species falls between 24°C and 27°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

The pH requirements of Oscar (6–7.5) and Sunset Hap (7.6–8.6) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 10–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Oscar and Sunset Hap together, plan for an aquarium of at least 458 litres with a minimum length of 150 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), Smooth Gravel (Sensitive Barbels), 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.

Why This Pairing Usually Fails in Practice

Oscar and Sunset Hap are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Oscar and Sunset Hap.

Frequently Asked Questions

Can Oscar and Sunset Hap live together?

No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.

What size tank do Oscar and Sunset Hap need?

A minimum of 458 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 Oscar and Sunset Hap together?

Keep the aquarium between 24°C and 27°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Oscar or Sunset Hap aggressive?

Oscar is semi-aggressive (7/10) and Sunset Hap is moderately assertive (6/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Oscar and Sunset Hap need?

Their pH requirements do not overlap. Oscar prefers 6–7.5, while Sunset Hap needs 7.6–8.6. This makes them incompatible in the same water chemistry.

How do I manage Oscar's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Oscar 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 4, 2026
Last updated
May 4, 2026
Issues or corrections?
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