Can Finger Fish and Fire Eel Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 4, 2026
Not Recommended

Finger Fish and Fire Eel are not recommended as tank mates due to incompatible water types. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Finger Fish

Monodactylus argenteus

Fire Eel

Mastacembelus erythrotaenia

🐟Family Group
Finger Fish
Oddballs
Fire Eel
Oddballs
Temperament
Finger Fish
Semi-Aggressive (5/10)
Fire Eel
Mostly Peaceful (4/10)
Temperature
✓ Compatible
Finger Fish
24–28°C
Fire Eel
24–28°C
pH Range
✓ Compatible
Finger Fish
7.5–8.5
Fire Eel
6–7.5
Hardness (dGH)
✓ Compatible
Finger Fish
12–30
Fire Eel
5–15
Water Type
✗ No overlap
Finger Fish
Brackish Required
Fire Eel
Freshwater Only
Flow Preference
✓ Compatible
Finger Fish
Moderate
Fire Eel
Moderate
Min Tank Volume
Combined: 702 L
Finger Fish
470 L
Fire Eel
680 L
Swimming Level
✓ Different zones
Finger Fish
Middle
Fire Eel
Bottom
🏷️Behavior Tags
Finger Fish
Hyperactive / Fast SwimmerFin NipperPlant DestroyerAggressive to same species/look-alikes
Fire Eel
Piscivore (Eats small/nano fish)Shrimp EaterDigger (Disturbs Substrate)Jumper (Lid Required)NocturnalShy / Slow Moving (Easily Stressed)
Stocking calculator

Can your tank handle Finger Fish and Fire 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.

Finger Fish
Fire Eel
Test both in my tank

Behaviour & Temperament

Finger Fish is a moderately assertive species (5/10), while Fire Eel is generally mild-mannered (4/10). This modest difference means Finger Fish may occasionally assert dominance over Fire Eel.

In terms of spatial distribution, Finger Fish prefers the Middle (Open Water) zone, whereas Fire Eel occupies the Bottom (Substrate) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

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

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

Water Parameters

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 12–15 dGH. Regular testing will ensure conditions stay within this range.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together.

Tank Setup

To house Finger Fish and Fire Eel together, plan for an aquarium of at least 702 litres with a minimum length of 180 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: Smooth Gravel (Sensitive Barbels), Sand (Sifters), 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

Finger Fish and Fire 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.

Frequently Asked Questions

Can Finger Fish and Fire Eel live together?

No. This combination is not recommended. Key incompatibilities — such as different water type needs — make cohabitation unsafe.

What size tank do Finger Fish and Fire Eel need?

A minimum of 702 litres (tank length at least 180 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 Finger Fish and Fire Eel together?

Keep the aquarium between 24°C and 28°C. A target of around 26.0°C sits comfortably within both species' preferred ranges.

Are Finger Fish or Fire Eel aggressive?

Finger Fish is moderately assertive (5/10) and Fire Eel is generally mild-mannered (4/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Finger Fish and Fire Eel need?

Both species overlap in the 7.5–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Will Finger Fish nip Fire Eel's fins?

Finger Fish is a known fin nipper. If Fire Eel has long or flowing fins, there is a real risk of fin damage. Keeping Finger Fish in a larger group can help redirect nipping behaviour toward conspecifics.

Does Fire Eel being nocturnal affect compatibility?

Fire 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 Fire Eel during evening hours.

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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