Can Betta Macrostoma and Zebra Spiny Eel Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 1, 2026
Not Recommended

Betta Macrostoma and Zebra Spiny Eel 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

Betta Macrostoma

Betta macrostoma

Zebra Spiny Eel

Mastacembelus zebrinus

🐠Family Group
Betta Macrostoma
Anabantoids
Zebra Spiny Eel
Oddballs
Temperament
Betta Macrostoma
Semi-Aggressive (6/10)
Zebra Spiny Eel
Peaceful (2/10)
Temperature
✓ Compatible
Betta Macrostoma
20–25°C
Zebra Spiny Eel
22–26°C
pH Range
✗ No overlap
Betta Macrostoma
4–6
Zebra Spiny Eel
6.8–8
Hardness (dGH)
✓ Compatible
Betta Macrostoma
0–5
Zebra Spiny Eel
5–15
Water Type
✓ Compatible
Betta Macrostoma
Freshwater Only
Zebra Spiny Eel
Freshwater Only
Flow Preference
✓ Compatible
Betta Macrostoma
Low
Zebra Spiny Eel
Moderate
Min Tank Volume
Combined: 110 L
Betta Macrostoma
80 L
Zebra Spiny Eel
110 L
Swimming Level
Shared: 1 zone
Betta Macrostoma
TopMiddleBottom
Zebra Spiny Eel
Bottom
🏷️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)
Zebra Spiny Eel
Digger (Disturbs Substrate)Jumper (Lid Required)Shrimp EaterFry PredatorShy / Slow Moving (Easily Stressed)Nocturnal
Stocking calculator

Can your tank handle Betta Macrostoma and Zebra Spiny Eel?

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
Zebra Spiny Eel
Test both in my tank

Behaviour & Temperament

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

Betta Macrostoma and Zebra Spiny Eel both frequent the 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.

Worth noting: Zebra Spiny Eel is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Betta Macrostoma is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 22°C and 25°C. Aim for the midpoint of this range (around 23.5°C) for optimal comfort.

The pH requirements of Betta Macrostoma (4–6) and Zebra Spiny Eel (6.8–8) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 5–5 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Betta Macrostoma and Zebra Spiny Eel together, plan for an aquarium of at least 110 litres with a minimum length of 80 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), Smooth Gravel (Sensitive Barbels), Plants - Densely 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.

Why This Pairing Usually Fails in Practice

Betta Macrostoma and Zebra Spiny Eel 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 Zebra Spiny Eel.

Show 12 more tank sizes

Frequently Asked Questions

Can Betta Macrostoma and Zebra Spiny Eel 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 Zebra Spiny Eel need?

A minimum of 110 litres (tank length at least 80 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 Zebra Spiny Eel together?

Keep the aquarium between 22°C and 25°C. A target of around 23.5°C sits comfortably within both species' preferred ranges.

Are Betta Macrostoma or Zebra Spiny Eel aggressive?

Betta Macrostoma is moderately assertive (6/10) and Zebra Spiny Eel 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 Zebra Spiny Eel need?

Their pH requirements do not overlap. Betta Macrostoma prefers 4–6, while Zebra Spiny Eel needs 6.8–8. 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.

Does Zebra Spiny Eel being nocturnal affect compatibility?

Zebra Spiny Eel is most active after lights-out, which naturally reduces daytime encounters with its tank mate. This can actually be beneficial, as both fish get undisturbed time to feed and explore. Just ensure food reaches Zebra Spiny Eel during evening hours.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
May 1, 2026
Last updated
May 1, 2026
Issues or corrections?
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