Can Betta Macrostoma and Boeseman's Rainbowfish Live Together?

Not Recommended

Betta Macrostoma and Boeseman's Rainbowfish are not recommended as tank mates due to no temperature overlap and 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

Betta Macrostoma

Betta macrostoma

Boeseman's Rainbowfish

Melanotaenia boesemani

🐠Family Group
Betta Macrostoma
Anabantoids
Boeseman's Rainbowfish
Rainbowfish
Temperament
Betta Macrostoma
Semi-Aggressive (6/10)
Boeseman's Rainbowfish
Peaceful (2/10)
Temperature
βœ— No overlap
Betta Macrostoma
20–25Β°C
Boeseman's Rainbowfish
26–30Β°C
pH Range
βœ— No overlap
Betta Macrostoma
4–6
Boeseman's Rainbowfish
7–8.1
Hardness (dGH)
βœ— No overlap
Betta Macrostoma
0–5
Boeseman's Rainbowfish
9–19
Water Type
βœ“ Compatible
Betta Macrostoma
Freshwater Only
Boeseman's Rainbowfish
Freshwater Only
Flow Preference
βœ“ Compatible
Betta Macrostoma
Low
Boeseman's Rainbowfish
Moderate
Min Tank Volume
Combined: 200 L
Betta Macrostoma
80 L
Boeseman's Rainbowfish
200 L
Swimming Level
Shared: 2 zones
Betta Macrostoma
TopMiddleBottom
Boeseman's Rainbowfish
TopMiddle
🏷️Behavior Tags
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)
Boeseman's Rainbowfish
Hyperactive / Fast SwimmerAggressive Eater (Starves shy fish)Jumper (Lid Required)
Stocking calculator

Can your tank handle Betta Macrostoma and Boeseman's Rainbowfish?

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.

Betta Macrostoma
Boeseman's Rainbowfish
Test both in my tank

Behaviour & Temperament

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

Betta Macrostoma and Boeseman's Rainbowfish 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. Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

Worth noting: Betta Macrostoma is a known jumper, so a tight-fitting lid is essential.

Water Parameters

There is no temperature overlap between Betta Macrostoma (20–25Β°C) and Boeseman's Rainbowfish (26–30Β°C). This fundamental mismatch makes long-term cohabitation impractical.

The pH requirements of Betta Macrostoma (4–6) and Boeseman's Rainbowfish (7–8.1) do not overlap, making it impossible to satisfy both species simultaneously.

Hardness requirements are incompatible: Betta Macrostoma needs 0–5 dGH while Boeseman's Rainbowfish requires 9–19 dGH.

Tank Setup

To house Betta Macrostoma and Boeseman's Rainbowfish together, plan for an aquarium of at least 200 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, Plants - lighly covered. 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.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Betta Macrostoma and Boeseman's Rainbowfish.

Show 5 more tank sizes

Diet & Feeding

Feeding time deserves special attention with this pairing. Boeseman's Rainbowfish is an aggressive eater that may prevent Betta Macrostoma from getting enough food.

Because Boeseman's Rainbowfish is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Betta Macrostoma receives an adequate share.

Frequently Asked Questions

Can Betta Macrostoma and Boeseman's Rainbowfish live together?

No. This combination is not recommended. Key incompatibilities β€” such as non-overlapping temperature ranges β€” make cohabitation unsafe.

What size tank do Betta Macrostoma and Boeseman's Rainbowfish need?

A minimum of 200 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 Boeseman's Rainbowfish together?

Unfortunately, there is no temperature range that satisfies both species. Betta Macrostoma requires 20–25Β°C, while Boeseman's Rainbowfish needs 26–30Β°C.

Are Betta Macrostoma or Boeseman's Rainbowfish aggressive?

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

What pH do Betta Macrostoma and Boeseman's Rainbowfish need?

Their pH requirements do not overlap. Betta Macrostoma prefers 4–6, while Boeseman's Rainbowfish needs 7–8.1. 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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