Can Molly (Sailfin/Black/Dalmatian) and Senegal Bichir Live Together?

🟡Possible with Caution

Keeping Molly (Sailfin/Black/Dalmatian) and Senegal Bichir together is possible but requires caution, though some care is needed. Provide a spacious tank of at least 240 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Molly (Sailfin/Black/Dalmatian)

Poecilia sphenops

Senegal Bichir

Polypterus senegalus

🐠Family Group
Molly (Sailfin/Black/Dalmatian)
Livebearers
Senegal Bichir
Oddballs
Temperament
Molly (Sailfin/Black/Dalmatian)
Mostly Peaceful (3/10)
Senegal Bichir
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
24–28°C
Senegal Bichir
25–29°C
pH Range
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
7.5–8.5
Senegal Bichir
6.2–7.8
Hardness (dGH)
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
12–30
Senegal Bichir
5–20
Water Type
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
Brackish Tolerant
Senegal Bichir
Freshwater Only
Flow Preference
✓ Compatible
Molly (Sailfin/Black/Dalmatian)
Moderate
Senegal Bichir
Low
Min Tank Volume
Combined: 240 L
Molly (Sailfin/Black/Dalmatian)
75 L
Senegal Bichir
200 L
Swimming Level
✓ Different zones
Molly (Sailfin/Black/Dalmatian)
TopMiddle
Senegal Bichir
Bottom
🏷️Behavior Tags
Molly (Sailfin/Black/Dalmatian)
Hyperactive / Fast SwimmerFry PredatorAggressive Eater (Starves shy fish)
Senegal Bichir
Piscivore (Eats small/nano fish)Shrimp EaterFry PredatorJumper (Lid Required)Nocturnal

Behaviour & Temperament

Molly (Sailfin/Black/Dalmatian) is a generally mild-mannered species (3/10), while Senegal Bichir is moderately assertive (6/10). This modest difference means Senegal Bichir may occasionally assert dominance over Molly (Sailfin/Black/Dalmatian).

In terms of spatial distribution, Molly (Sailfin/Black/Dalmatian) prefers the Top (Surface) and Middle (Open Water) zones, whereas Senegal Bichir 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: Senegal Bichir is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Senegal Bichir is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 25°C and 28°C. Aim for the midpoint of this range (around 26.5°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 and 7.8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 12–20 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Molly (Sailfin/Black/Dalmatian) and Senegal Bichir together, plan for an aquarium of at least 240 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.

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, Established Algae (Otocinclus), Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding). 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

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Frequently Asked Questions

Can Molly (Sailfin/Black/Dalmatian) and Senegal Bichir live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 240 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Molly (Sailfin/Black/Dalmatian) and Senegal Bichir need?

A minimum of 240 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 Molly (Sailfin/Black/Dalmatian) and Senegal Bichir together?

Keep the aquarium between 25°C and 28°C. A target of around 26.5°C sits comfortably within both species' preferred ranges.

Are Molly (Sailfin/Black/Dalmatian) or Senegal Bichir aggressive?

Molly (Sailfin/Black/Dalmatian) is generally mild-mannered (3/10) and Senegal Bichir is moderately assertive (6/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Molly (Sailfin/Black/Dalmatian) and Senegal Bichir need?

Both species overlap in the 7.5–7.8 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

Does Senegal Bichir being nocturnal affect compatibility?

Senegal 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 Senegal Bichir during evening hours.


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