Can Japanese Ricefish (Medaka) and Reticulated Hillstream Loach Live Together?

🟢Ideal Tank Mates

Yes, Japanese Ricefish (Medaka) and Reticulated Hillstream Loach are ideal tank mates. Both species share compatible water parameters and peaceful temperaments, making them well-suited for a community aquarium. They occupy different areas of the water column, which reduces competition for space. A minimum tank size of 96 litres is recommended.


At a Glance

Japanese Ricefish (Medaka)

Oryzias latipes

Reticulated Hillstream Loach

Sewellia lineolata

🐠Family Group
Japanese Ricefish (Medaka)
Killifish
Reticulated Hillstream Loach
Loaches
Temperament
Japanese Ricefish (Medaka)
Peaceful (2/10)
Reticulated Hillstream Loach
Mostly Peaceful (3/10)
Temperature
✓ Compatible
Japanese Ricefish (Medaka)
10–28°C
Reticulated Hillstream Loach
20–24°C
pH Range
✓ Compatible
Japanese Ricefish (Medaka)
6.5–8.5
Reticulated Hillstream Loach
6.5–7.5
Hardness (dGH)
✓ Compatible
Japanese Ricefish (Medaka)
5–25
Reticulated Hillstream Loach
4–15
Water Type
✓ Compatible
Japanese Ricefish (Medaka)
Brackish Tolerant
Reticulated Hillstream Loach
Freshwater Only
Flow Preference
✗ No overlap
Japanese Ricefish (Medaka)
Low
Reticulated Hillstream Loach
High
Min Tank Volume
Combined: 96 L
Japanese Ricefish (Medaka)
19 L
Reticulated Hillstream Loach
80 L
Swimming Level
✓ Different zones
Japanese Ricefish (Medaka)
Top
Reticulated Hillstream Loach
Bottom
🏷️Behavior Tags
Japanese Ricefish (Medaka)
Nano / Bite-sized (Predation Risk)Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Reticulated Hillstream Loach
Hyperactive / Fast SwimmerTerritorial (Defends specific area)

Behaviour & Temperament

Japanese Ricefish (Medaka) is a peaceful species (2/10), while Reticulated Hillstream Loach is generally mild-mannered (3/10). This modest difference means Reticulated Hillstream Loach may occasionally assert dominance over Japanese Ricefish (Medaka).

In terms of spatial distribution, Japanese Ricefish (Medaka) prefers the Top (Surface) zone, whereas Reticulated Hillstream Loach 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.

Worth noting: Japanese Ricefish (Medaka) is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 20°C and 24°C. Aim for the midpoint of this range (around 22.0°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 5–15 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Japanese Ricefish (Medaka) and Reticulated Hillstream Loach together, plan for an aquarium of at least 96 litres with a minimum length of 90 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, Smooth Gravel (Sensitive Barbels), Established Algae (Otocinclus), Plants - lighly covered. Meeting these requirements will help both species thrive.

Japanese Ricefish (Medaka) prefers Low (Still Water) flow while Reticulated Hillstream Loach needs High (River/Stream) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

Find the right tank equipment

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

Frequently Asked Questions

Can Japanese Ricefish (Medaka) and Reticulated Hillstream Loach live together?

Yes. Japanese Ricefish (Medaka) and Reticulated Hillstream Loach are considered ideal tank mates. Their water parameters, temperaments, and behaviour profiles are well matched for a community aquarium.

What size tank do Japanese Ricefish (Medaka) and Reticulated Hillstream Loach need?

A minimum of 96 litres (tank length at least 90 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 Japanese Ricefish (Medaka) and Reticulated Hillstream Loach together?

Keep the aquarium between 20°C and 24°C. A target of around 22.0°C sits comfortably within both species' preferred ranges.

Are Japanese Ricefish (Medaka) or Reticulated Hillstream Loach aggressive?

Japanese Ricefish (Medaka) is peaceful (2/10) and Reticulated Hillstream Loach is generally mild-mannered (3/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Japanese Ricefish (Medaka) and Reticulated Hillstream Loach 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.

How do I manage Reticulated Hillstream Loach's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Reticulated Hillstream Loach space to claim a territory without encroaching on the other fish's area. Adding décor that divides the tank into distinct zones works especially well.


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