Can Bucktooth Tetra (Exodon) and Fire Eel Live Together?

🔴Not Recommended

Bucktooth Tetra (Exodon) and Fire Eel are not recommended as tank mates due to eye biters attack slow-moving fish, risking permanent injury.. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Bucktooth Tetra (Exodon)

Exodon paradoxus

Fire Eel

Mastacembelus erythrotaenia

🐠Family Group
Bucktooth Tetra (Exodon)
Characins
Fire Eel
Oddballs
Temperament
Bucktooth Tetra (Exodon)
Highly Aggressive (9/10)
Fire Eel
Mostly Peaceful (4/10)
Temperature
✓ Compatible
Bucktooth Tetra (Exodon)
23–28°C
Fire Eel
24–28°C
pH Range
✓ Compatible
Bucktooth Tetra (Exodon)
5.5–7.5
Fire Eel
6–7.5
Hardness (dGH)
✓ Compatible
Bucktooth Tetra (Exodon)
1–15
Fire Eel
5–15
Water Type
✓ Compatible
Bucktooth Tetra (Exodon)
Freshwater Only
Fire Eel
Freshwater Only
Flow Preference
✓ Compatible
Bucktooth Tetra (Exodon)
Moderate
Fire Eel
Moderate
Min Tank Volume
Combined: 816 L
Bucktooth Tetra (Exodon)
200 L
Fire Eel
680 L
Swimming Level
✓ Different zones
Bucktooth Tetra (Exodon)
MiddleTop
Fire Eel
Bottom
🏷️Behavior Tags
Bucktooth Tetra (Exodon)
Generally AggressiveAggressive to same species/look-alikesFin NipperPiscivore (Eats small/nano fish)Hyperactive / Fast SwimmerEye Biter (Attacks slow moving fish)Jumper (Lid Required)
Fire Eel
Piscivore (Eats small/nano fish)Shrimp EaterDigger (Disturbs Substrate)Jumper (Lid Required)NocturnalShy / Slow Moving (Easily Stressed)

Behaviour & Temperament

Bucktooth Tetra (Exodon) is a highly aggressive species (9/10), while Fire Eel is generally mild-mannered (4/10). This notable difference means Bucktooth Tetra (Exodon) may occasionally assert dominance over Fire Eel.

In terms of spatial distribution, Bucktooth Tetra (Exodon) prefers the Middle (Open Water) and Top (Surface) zones, 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.

There is a critical concern: the Eye Biter (Attacks slow moving fish) behaviour of one fish directly conflicts with the Shy / Slow Moving (Easily Stressed) trait of the other — eye biters attack slow-moving fish, risking permanent injury..

Additional behavioural considerations to keep in mind: Aggressive fish may bully and stress shy, slow-moving species. 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, Bucktooth Tetra (Exodon) 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 6 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 5–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Bucktooth Tetra (Exodon) and Fire Eel together, plan for an aquarium of at least 816 litres with a minimum length of 180 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

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: Driftwood (Digestion/Hiding), Sand (Sifters), Smooth Gravel (Sensitive Barbels). 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.

Frequently Asked Questions

Can Bucktooth Tetra (Exodon) and Fire Eel live together?

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

What size tank do Bucktooth Tetra (Exodon) and Fire Eel need?

A minimum of 816 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 Bucktooth Tetra (Exodon) 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 Bucktooth Tetra (Exodon) or Fire Eel aggressive?

Bucktooth Tetra (Exodon) is highly aggressive (9/10) and Fire Eel is generally mild-mannered (4/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Bucktooth Tetra (Exodon) and Fire Eel need?

Both species overlap in the 6–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Will Bucktooth Tetra (Exodon) nip Fire Eel's fins?

Bucktooth Tetra (Exodon) is a known fin nipper. If Fire Eel has long or flowing fins, there is a real risk of fin damage. Keeping Bucktooth Tetra (Exodon) 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.


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