Can Ajamaru Rainbowfish and Threadfin Rainbowfish Live Together?

Possible with Caution

Keeping Ajamaru Rainbowfish and Threadfin Rainbowfish together is possible but requires caution due to potential behavioral clashes. Provide a spacious tank of at least 150 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Ajamaru Rainbowfish

Melanotaenia ajamaruensis

Threadfin Rainbowfish

Iriatherina werneri

🐟Family Group
Ajamaru Rainbowfish
Rainbowfish
Threadfin Rainbowfish
Rainbowfish
Temperament
Ajamaru Rainbowfish
Peaceful (2/10)
Threadfin Rainbowfish
Peaceful (1/10)
Temperature
✓ Compatible
Ajamaru Rainbowfish
24–28°C
Threadfin Rainbowfish
23–29°C
pH Range
✓ Compatible
Ajamaru Rainbowfish
7.2–8.5
Threadfin Rainbowfish
5.5–7.5
Hardness (dGH)
✓ Compatible
Ajamaru Rainbowfish
8–20
Threadfin Rainbowfish
1–12
Water Type
✓ Compatible
Ajamaru Rainbowfish
Freshwater Only
Threadfin Rainbowfish
Freshwater Only
Flow Preference
✓ Compatible
Ajamaru Rainbowfish
Moderate
Threadfin Rainbowfish
Low
Min Tank Volume
Combined: 150 L
Ajamaru Rainbowfish
150 L
Threadfin Rainbowfish
60 L
Swimming Level
Shared: 2 zones
Ajamaru Rainbowfish
TopMiddle
Threadfin Rainbowfish
TopMiddle
🏷️Behavior Tags
Ajamaru Rainbowfish
Hyperactive / Fast SwimmerJumper (Lid Required)Fry Predator
Threadfin Rainbowfish
Nano / Bite-sized (Predation Risk)Shy / Slow Moving (Easily Stressed)Jumper (Lid Required)Hyperactive / Fast SwimmerAggressive Eater (Starves shy fish)
Stocking calculator

Can your tank handle Ajamaru Rainbowfish and Threadfin Rainbowfish?

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.

Ajamaru Rainbowfish
Threadfin Rainbowfish
Test both in my tank

Behaviour & Temperament

Ajamaru Rainbowfish is a peaceful species (2/10), while Threadfin Rainbowfish is peaceful (1/10). This modest difference means Ajamaru Rainbowfish may occasionally assert dominance over Threadfin Rainbowfish.

Ajamaru Rainbowfish and Threadfin Rainbowfish both frequent the Top (Surface) and Middle (Open Water) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Ajamaru Rainbowfish is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat.

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 7.2 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 8–12 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Ajamaru Rainbowfish and Threadfin Rainbowfish together, plan for an aquarium of at least 150 litres with a minimum length of 90 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

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.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Ajamaru Rainbowfish and Threadfin Rainbowfish.

Show 9 more tank sizes

Frequently Asked Questions

Can Ajamaru Rainbowfish and Threadfin Rainbowfish live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 150 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Ajamaru Rainbowfish and Threadfin Rainbowfish need?

A minimum of 150 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 Ajamaru Rainbowfish and Threadfin Rainbowfish 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 Ajamaru Rainbowfish or Threadfin Rainbowfish aggressive?

Ajamaru Rainbowfish is peaceful (2/10) and Threadfin Rainbowfish is peaceful (1/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Ajamaru Rainbowfish and Threadfin Rainbowfish need?

Both species overlap in the 7.2–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.


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