Can Cardinal Tetra and Violet Goby (Dragon Goby) Live Together?
Cardinal Tetra and Violet Goby (Dragon Goby) are not recommended as tank mates due to incompatible water types 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
Behaviour & Temperament
Cardinal Tetra is a peaceful species (1/10), while Violet Goby (Dragon Goby) is peaceful (2/10). This modest difference means Violet Goby (Dragon Goby) may occasionally assert dominance over Cardinal Tetra.
In terms of spatial distribution, Cardinal Tetra prefers the Middle (Open Water) zone, whereas Violet Goby (Dragon Goby) 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: Violet Goby (Dragon Goby) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters.
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.
The pH requirements of Cardinal Tetra (4–7) and Violet Goby (Dragon Goby) (7.5–8.5) do not overlap, making it impossible to satisfy both species simultaneously.
Hardness requirements are incompatible: Cardinal Tetra needs 1–8 dGH while Violet Goby (Dragon Goby) requires 12–25 dGH.
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 Cardinal Tetra and Violet Goby (Dragon Goby) 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: Leaf Litter/Blackwater, Driftwood (Digestion/Hiding), Plants - Densely covered, Sand (Sifters), Shells (Breeding/Hiding). 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.
Frequently Asked Questions
Can Cardinal Tetra and Violet Goby (Dragon Goby) live together?▾
No. This combination is not recommended. Key incompatibilities — such as different water type needs — make cohabitation unsafe.
What size tank do Cardinal Tetra and Violet Goby (Dragon Goby) 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 Cardinal Tetra and Violet Goby (Dragon Goby) 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 Cardinal Tetra or Violet Goby (Dragon Goby) aggressive?▾
Cardinal Tetra is peaceful (1/10) and Violet Goby (Dragon Goby) is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.
What pH do Cardinal Tetra and Violet Goby (Dragon Goby) need?▾
Their pH requirements do not overlap. Cardinal Tetra prefers 4–7, while Violet Goby (Dragon Goby) needs 7.5–8.5. This makes them incompatible in the same water chemistry.
Does Violet Goby (Dragon Goby) being nocturnal affect compatibility?▾
Violet Goby (Dragon Goby) 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 Violet Goby (Dragon Goby) during evening hours.
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