Can Betta Macrostoma and Redear Sunfish Live Together?
Betta Macrostoma and Redear Sunfish are not recommended as tank mates due to conflicting pH requirements and incompatible hardness ranges. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.
At a Glance
Can your tank handle Betta Macrostoma and Redear Sunfish?
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.
Behaviour & Temperament
Both Betta Macrostoma and Redear Sunfish are moderately assertive species with an aggression score of 6/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.
Betta Macrostoma and Redear Sunfish 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.
Worth noting: Betta Macrostoma is a known jumper, so a tight-fitting lid is essential.
Water Parameters
The safe temperature window for both species falls between 20°C and 25°C. Aim for the midpoint of this range (around 22.5°C) for optimal comfort.
The pH requirements of Betta Macrostoma (4–6) and Redear Sunfish (6.5–8.5) do not overlap, making it impossible to satisfy both species simultaneously.
Hardness requirements are incompatible: Betta Macrostoma needs 0–5 dGH while Redear Sunfish requires 8–20 dGH.
Tank Setup
To house Betta Macrostoma and Redear Sunfish together, plan for an aquarium of at least 280 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.
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: Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Plants - Floating, Sand (Sifters), Shells (Breeding/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.
Why This Pairing Usually Fails in Practice
Betta Macrostoma and Redear Sunfish 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 Betta Macrostoma and Redear Sunfish.
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
150 Gallon High
180 Gallon Standard
350 Liter (120cm Deep)
Show 1 more tank size
Frequently Asked Questions
Can Betta Macrostoma and Redear Sunfish live together?
No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.
What size tank do Betta Macrostoma and Redear Sunfish need?
A minimum of 280 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 Betta Macrostoma and Redear Sunfish together?
Keep the aquarium between 20°C and 25°C. A target of around 22.5°C sits comfortably within both species' preferred ranges.
Are Betta Macrostoma or Redear Sunfish aggressive?
Betta Macrostoma is moderately assertive (6/10) and Redear Sunfish is moderately assertive (6/10). Their similar temperaments generally lead to a peaceful coexistence.
What pH do Betta Macrostoma and Redear Sunfish need?
Their pH requirements do not overlap. Betta Macrostoma prefers 4–6, while Redear Sunfish needs 6.5–8.5. This makes them incompatible in the same water chemistry.
How do I manage Betta Macrostoma's territorial behaviour?
Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Betta Macrostoma 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.
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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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