Can Reedfish (Ropefish) and Threadfin Rainbowfish Live Together?

🔴Not Recommended

Reedfish (Ropefish) and Threadfin Rainbowfish 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

Reedfish (Ropefish)

Erpetoichthys calabaricus

Threadfin Rainbowfish

Iriatherina werneri

🐠Family Group
Reedfish (Ropefish)
Oddballs
Threadfin Rainbowfish
Rainbowfish
Temperament
Reedfish (Ropefish)
Mostly Peaceful (3/10)
Threadfin Rainbowfish
Peaceful (1/10)
Temperature
✓ Compatible
Reedfish (Ropefish)
22–28°C
Threadfin Rainbowfish
23–29°C
pH Range
✓ Compatible
Reedfish (Ropefish)
6–7.5
Threadfin Rainbowfish
5.5–7.5
Hardness (dGH)
✓ Compatible
Reedfish (Ropefish)
5–20
Threadfin Rainbowfish
1–12
Water Type
✓ Compatible
Reedfish (Ropefish)
Freshwater Only
Threadfin Rainbowfish
Freshwater Only
Flow Preference
✓ Compatible
Reedfish (Ropefish)
Low
Threadfin Rainbowfish
Low
Min Tank Volume
Combined: 216 L
Reedfish (Ropefish)
180 L
Threadfin Rainbowfish
60 L
Swimming Level
Shared: 1 zone
Reedfish (Ropefish)
BottomMiddle
Threadfin Rainbowfish
TopMiddle
🏷️Behavior Tags
Reedfish (Ropefish)
Piscivore (Eats small/nano fish)Shrimp EaterJumper (Lid Required)NocturnalHyperactive / Fast SwimmerSlime Coat Eater (Attacks Flat Fish)
Threadfin Rainbowfish
Nano / Bite-sized (Predation Risk)Shy / Slow Moving (Easily Stressed)Jumper (Lid Required)Hyperactive / Fast SwimmerAggressive Eater (Starves shy fish)

Behaviour & Temperament

Reedfish (Ropefish) is a generally mild-mannered species (3/10), while Threadfin Rainbowfish is peaceful (1/10). This modest difference means Reedfish (Ropefish) may occasionally assert dominance over Threadfin Rainbowfish.

Reedfish (Ropefish) and Threadfin Rainbowfish both frequent the 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.

There are critical concerns: 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.. Additionally, the Slime Coat Eater (Attacks Flat Fish) behaviour of one fish directly conflicts with the Shy / Slow Moving (Easily Stressed) trait of the other — slime coat eaters target slow-moving fish, causing severe stress and health issues..

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Shrimp eaters may also prey on very small nano fish.

Worth noting: Reedfish (Ropefish) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Reedfish (Ropefish) is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 23°C and 28°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

Both fish can tolerate a pH between 6 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 5–12 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Reedfish (Ropefish) and Threadfin Rainbowfish together, plan for an aquarium of at least 216 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: Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding), Plants - Densely covered, Plants - Floating. 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.

Find the right tank equipment

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

Diet & Feeding

Feeding time deserves special attention with this pairing. Reedfish (Ropefish) is a known shrimp eater and may prey on small invertebrates or nano fish like Threadfin Rainbowfish.

Because Threadfin Rainbowfish is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Reedfish (Ropefish) receives an adequate share.

Frequently Asked Questions

Can Reedfish (Ropefish) and Threadfin Rainbowfish live together?

No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.

What size tank do Reedfish (Ropefish) and Threadfin Rainbowfish need?

A minimum of 216 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 Reedfish (Ropefish) and Threadfin Rainbowfish together?

Keep the aquarium between 23°C and 28°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Reedfish (Ropefish) or Threadfin Rainbowfish aggressive?

Reedfish (Ropefish) is generally mild-mannered (3/10) and Threadfin Rainbowfish is peaceful (1/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Reedfish (Ropefish) and Threadfin Rainbowfish need?

Both species overlap in the 6–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Does Reedfish (Ropefish) being nocturnal affect compatibility?

Reedfish (Ropefish) 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 Reedfish (Ropefish) during evening hours.


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