Can Bucktooth Tetra (Exodon) and Japanese Ricefish (Medaka) Live Together?
Bucktooth Tetra (Exodon) and Japanese Ricefish (Medaka) are not recommended as tank mates due to piscivorous fish will prey on nano-sized tank mates.. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.
At a Glance
Behaviour & Temperament
Bucktooth Tetra (Exodon) is a highly aggressive species (9/10), while Japanese Ricefish (Medaka) is peaceful (2/10). This notable difference means Bucktooth Tetra (Exodon) may occasionally assert dominance over Japanese Ricefish (Medaka).
Large aggression gap (7 points) between Bucktooth Tetra (Exodon) and Japanese Ricefish (Medaka) increases stress risk for the more peaceful fish.
Bucktooth Tetra (Exodon) and Japanese Ricefish (Medaka) both frequent the Top (Surface) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.
There is a critical concern: the Piscivore (Eats small/nano fish) behaviour of one fish directly conflicts with the Nano / Bite-sized (Predation Risk) trait of the other — piscivorous fish will prey on nano-sized tank mates..
Worth noting: 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 23°C and 28°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.
Both fish can tolerate a pH between 6.5 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 5–15 dGH. Regular testing will ensure conditions stay within this range.
Tank Setup
To house Bucktooth Tetra (Exodon) and Japanese Ricefish (Medaka) together, plan for an aquarium of at least 240 litres with a minimum length of 120 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), Plants - Densely covered, 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.
Frequently Asked Questions
Can Bucktooth Tetra (Exodon) and Japanese Ricefish (Medaka) 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 Japanese Ricefish (Medaka) need?▾
A minimum of 240 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 Bucktooth Tetra (Exodon) and Japanese Ricefish (Medaka) together?▾
Keep the aquarium between 23°C and 28°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.
Are Bucktooth Tetra (Exodon) or Japanese Ricefish (Medaka) aggressive?▾
Bucktooth Tetra (Exodon) is highly aggressive (9/10) and Japanese Ricefish (Medaka) is peaceful (2/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.
What pH do Bucktooth Tetra (Exodon) and Japanese Ricefish (Medaka) need?▾
Both species overlap in the 6.5–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.
Will Bucktooth Tetra (Exodon) nip Japanese Ricefish (Medaka)'s fins?▾
Bucktooth Tetra (Exodon) is a known fin nipper. If Japanese Ricefish (Medaka) 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.
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