Can Forktail Blue-eye and Japanese Ricefish (Medaka) Live Together?

🟢Ideal Tank Mates

Yes, Forktail Blue-eye and Japanese Ricefish (Medaka) are ideal tank mates. Both species share compatible water parameters and peaceful temperaments, making them well-suited for a community aquarium. A minimum tank size of 66 litres is recommended.


At a Glance

Forktail Blue-eye

Pseudomugil furcatus

Japanese Ricefish (Medaka)

Oryzias latipes

🐠Family Group
Forktail Blue-eye
Rainbowfish
Japanese Ricefish (Medaka)
Killifish
Temperament
Forktail Blue-eye
Peaceful (2/10)
Japanese Ricefish (Medaka)
Peaceful (2/10)
Temperature
✓ Compatible
Forktail Blue-eye
24–28°C
Japanese Ricefish (Medaka)
10–28°C
pH Range
✓ Compatible
Forktail Blue-eye
7–8
Japanese Ricefish (Medaka)
6.5–8.5
Hardness (dGH)
✓ Compatible
Forktail Blue-eye
5–15
Japanese Ricefish (Medaka)
5–25
Water Type
✓ Compatible
Forktail Blue-eye
Freshwater Only
Japanese Ricefish (Medaka)
Brackish Tolerant
Flow Preference
✓ Compatible
Forktail Blue-eye
Moderate
Japanese Ricefish (Medaka)
Low
Min Tank Volume
Combined: 66 L
Forktail Blue-eye
55 L
Japanese Ricefish (Medaka)
19 L
Swimming Level
Shared: 1 zone
Forktail Blue-eye
TopMiddle
Japanese Ricefish (Medaka)
Top
🏷️Behavior Tags
Forktail Blue-eye
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)
Japanese Ricefish (Medaka)
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator

Behaviour & Temperament

Both Forktail Blue-eye and Japanese Ricefish (Medaka) are peaceful species with an aggression score of 2/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Forktail Blue-eye 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.

Worth noting: Forktail Blue-eye 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 and 8. 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. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Forktail Blue-eye and Japanese Ricefish (Medaka) together, plan for an aquarium of at least 66 litres with a minimum length of 60 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: 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.

Find the right tank equipment

Browse tanks, décor, and equipment suited for this setup.

Frequently Asked Questions

Can Forktail Blue-eye and Japanese Ricefish (Medaka) live together?

Yes. Forktail Blue-eye and Japanese Ricefish (Medaka) are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Forktail Blue-eye and Japanese Ricefish (Medaka) need?

A minimum of 66 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 Forktail Blue-eye and Japanese Ricefish (Medaka) 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 Forktail Blue-eye or Japanese Ricefish (Medaka) aggressive?

Forktail Blue-eye is peaceful (2/10) and Japanese Ricefish (Medaka) is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Forktail Blue-eye and Japanese Ricefish (Medaka) need?

Both species overlap in the 7–8 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.


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