Can Ajamaru Rainbowfish and Betta Macrostoma Live Together?

Not Recommended

Ajamaru Rainbowfish and Betta Macrostoma 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

Ajamaru Rainbowfish

Melanotaenia ajamaruensis

Betta Macrostoma

Betta macrostoma

🐠Family Group
Ajamaru Rainbowfish
Rainbowfish
Betta Macrostoma
Anabantoids
Temperament
Ajamaru Rainbowfish
Peaceful (2/10)
Betta Macrostoma
Semi-Aggressive (6/10)
Temperature
βœ“ Compatible
Ajamaru Rainbowfish
24–28Β°C
Betta Macrostoma
20–25Β°C
pH Range
βœ— No overlap
Ajamaru Rainbowfish
7.2–8.5
Betta Macrostoma
4–6
Hardness (dGH)
βœ— No overlap
Ajamaru Rainbowfish
8–20
Betta Macrostoma
0–5
Water Type
βœ“ Compatible
Ajamaru Rainbowfish
Freshwater Only
Betta Macrostoma
Freshwater Only
Flow Preference
βœ“ Compatible
Ajamaru Rainbowfish
Moderate
Betta Macrostoma
Low
Min Tank Volume
Combined: 150 L
Ajamaru Rainbowfish
150 L
Betta Macrostoma
80 L
Swimming Level
Shared: 2 zones
Ajamaru Rainbowfish
TopMiddle
Betta Macrostoma
TopMiddleBottom
🏷️Behavior Tags
Ajamaru Rainbowfish
Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Betta Macrostoma
Piscivore (Eats small/nano fish)Shrimp EaterJumper (Lid Required)Aggressive to same species/look-alikesShy / Slow Moving (Easily Stressed)Territorial (Defends specific area)
Stocking calculator

Can your tank handle Ajamaru Rainbowfish and Betta Macrostoma?

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.

Ajamaru Rainbowfish
Betta Macrostoma
Test both in my tank

Behaviour & Temperament

Ajamaru Rainbowfish is a peaceful species (2/10), while Betta Macrostoma is moderately assertive (6/10). This notable difference means Betta Macrostoma may occasionally assert dominance over Ajamaru Rainbowfish.

Ajamaru Rainbowfish and Betta Macrostoma both frequent the Top (Surface) 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.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Ajamaru Rainbowfish is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 24Β°C and 25Β°C. Aim for the midpoint of this range (around 24.5Β°C) for optimal comfort.

The pH requirements of Ajamaru Rainbowfish (7.2–8.5) and Betta Macrostoma (4–6) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Ajamaru Rainbowfish needs 8–20 dGH while Betta Macrostoma requires 0–5 dGH.

Tank Setup

To house Ajamaru Rainbowfish and Betta Macrostoma together, plan for an aquarium of at least 150 litres with a minimum length of 90 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: Plants - Densely covered, Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Plants - Floating. 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.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Ajamaru Rainbowfish and Betta Macrostoma.

Show 9 more tank sizes

Frequently Asked Questions

Can Ajamaru Rainbowfish and Betta Macrostoma live together?

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

What size tank do Ajamaru Rainbowfish and Betta Macrostoma need?

A minimum of 150 litres (tank length at least 90 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 Ajamaru Rainbowfish and Betta Macrostoma together?

Keep the aquarium between 24Β°C and 25Β°C. A target of around 24.5Β°C sits comfortably within both species' preferred ranges.

Are Ajamaru Rainbowfish or Betta Macrostoma aggressive?

Ajamaru Rainbowfish is peaceful (2/10) and Betta Macrostoma is moderately assertive (6/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Ajamaru Rainbowfish and Betta Macrostoma need?

Their pH requirements do not overlap. Ajamaru Rainbowfish prefers 7.2–8.5, while Betta Macrostoma needs 4–6. 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 dΓ©cor that divides the tank into distinct zones works especially well.


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