Can Saddled Bichir and Threadfin Rainbowfish Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 11, 2026
Not Recommended

Saddled Bichir 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

Saddled Bichir

Polypterus endlicheri

Threadfin Rainbowfish

Iriatherina werneri

🐠Family Group
Saddled Bichir
Oddballs
Threadfin Rainbowfish
Rainbowfish
Temperament
Saddled Bichir
Semi-Aggressive (6/10)
Threadfin Rainbowfish
Peaceful (1/10)
Temperature
✓ Compatible
Saddled Bichir
24–30°C
Threadfin Rainbowfish
23–29°C
pH Range
✓ Compatible
Saddled Bichir
6–8
Threadfin Rainbowfish
5.5–7.5
Hardness (dGH)
✓ Compatible
Saddled Bichir
5–20
Threadfin Rainbowfish
1–12
Water Type
✓ Compatible
Saddled Bichir
Freshwater Only
Threadfin Rainbowfish
Freshwater Only
Flow Preference
✓ Compatible
Saddled Bichir
Moderate
Threadfin Rainbowfish
Low
Min Tank Volume
Combined: 650 L
Saddled Bichir
650 L
Threadfin Rainbowfish
60 L
Swimming Level
✓ Different zones
Saddled Bichir
Bottom
Threadfin Rainbowfish
TopMiddle
🏷️Behavior Tags
Saddled Bichir
Piscivore (Eats small/nano fish)NocturnalJumper (Lid Required)
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 Saddled Bichir 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.

Saddled Bichir
Threadfin Rainbowfish
Test both in my tank

Behaviour & Temperament

Saddled Bichir is a moderately assertive species (6/10), while Threadfin Rainbowfish is peaceful (1/10). This notable difference means Saddled Bichir may occasionally assert dominance over Threadfin Rainbowfish.

In terms of spatial distribution, Saddled Bichir prefers the Bottom (Substrate) zone, whereas Threadfin Rainbowfish occupies the Top (Surface) and Middle (Open Water) zones. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

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..

Worth noting: Saddled Bichir is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Saddled Bichir 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 29°C. Aim for the midpoint of this range (around 26.5°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.

Tank Setup

To house Saddled Bichir and Threadfin Rainbowfish together, plan for an aquarium of at least 650 litres with a minimum length of 180 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: 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 moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

Why This Pairing Usually Fails in Practice

Saddled Bichir and Threadfin Rainbowfish are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Saddled Bichir and Threadfin Rainbowfish.

Frequently Asked Questions

Can Saddled Bichir 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 Saddled Bichir and Threadfin Rainbowfish need?

A minimum of 650 litres (tank length at least 180 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 Saddled Bichir and Threadfin Rainbowfish together?

Keep the aquarium between 24°C and 29°C. A target of around 26.5°C sits comfortably within both species' preferred ranges.

Are Saddled Bichir or Threadfin Rainbowfish aggressive?

Saddled Bichir is moderately assertive (6/10) and Threadfin Rainbowfish is peaceful (1/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Saddled Bichir 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 Saddled Bichir being nocturnal affect compatibility?

Saddled Bichir 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 Saddled Bichir during evening hours.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
May 11, 2026
Last updated
May 11, 2026
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