Can Golden Wonder Killifish and Japanese Ricefish (Medaka) Live Together?
Golden Wonder Killifish 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
Can your tank handle Golden Wonder Killifish and Japanese Ricefish (Medaka)?
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.
Shared setup supplies
We may earn from qualifying purchases
Behaviour & Temperament
Golden Wonder Killifish is a moderately assertive species (6/10), while Japanese Ricefish (Medaka) is peaceful (2/10). This notable difference means Golden Wonder Killifish may occasionally assert dominance over Japanese Ricefish (Medaka).
Golden Wonder Killifish 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..
Additional behavioural considerations to keep in mind: Shrimp eaters may also prey on very small nano fish.
Worth noting: Golden Wonder Killifish 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 28°C. Aim for the midpoint of this range (around 25.0°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 5–20 dGH. Regular testing will ensure conditions stay within this range.
Water care products
We may earn from qualifying purchases
Tank Setup
To house Golden Wonder Killifish and Japanese Ricefish (Medaka) together, plan for an aquarium of at least 75 litres with a minimum length of 60 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: Plants - Floating, 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.
Suitable Tank Sizes
Standard aquarium sizes large enough for both Golden Wonder Killifish and Japanese Ricefish (Medaka).
20 Gallon High
20 Gallon Long
29 Gallon Standard
30 Gallon Breeder
36 Gallon Bowfront
40 Gallon Breeder
Show 17 more tank sizes
Diet & Feeding
Feeding time deserves special attention with this pairing. Golden Wonder Killifish is a known shrimp eater and may prey on small invertebrates or nano fish like Japanese Ricefish (Medaka).
Feeding products to consider
We may earn from qualifying purchases
.webp?2026-04-25T14%3A35%3A38.022Z)
Frequently Asked Questions
Can Golden Wonder Killifish 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 Golden Wonder Killifish and Japanese Ricefish (Medaka) need?
A minimum of 75 litres (tank length at least 60 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 Golden Wonder Killifish and Japanese Ricefish (Medaka) together?
Keep the aquarium between 22°C and 28°C. A target of around 25.0°C sits comfortably within both species' preferred ranges.
Are Golden Wonder Killifish or Japanese Ricefish (Medaka) aggressive?
Golden Wonder Killifish is moderately assertive (6/10) 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 Golden Wonder Killifish 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.
Related Comparisons
Golden Wonder Killifish & Florida Flagfish
·
Golden Wonder Killifish & Gardner's Killifish
·
Golden Wonder Killifish & Clown Killifish
·
Golden Wonder Killifish & African Butterfly Fish
·
Golden Wonder Killifish & African Clawed Frog
·
Golden Wonder Killifish & Banded Gourami
·
Japanese Ricefish (Medaka) & Norman's Lampeye Killifish
·
Japanese Ricefish (Medaka) & Rachov's Killifish (Annual)
·
Japanese Ricefish (Medaka) & Balloon Molly
·
Japanese Ricefish (Medaka) & Guppy
·
Japanese Ricefish (Medaka) & Least Killifish (Heterandria)
·
Japanese Ricefish (Medaka) & African Dwarf Frog
·