Can Bentos Tetra and Molly (Sailfin/Black/Dalmatian) Live Together?

Possible with Caution

Keeping Bentos Tetra and Molly (Sailfin/Black/Dalmatian) together is possible but requires caution due to potential behavioral clashes. Provide a spacious tank of at least 75 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Bentos Tetra

Hyphessobrycon bentosi

Molly (Sailfin/Black/Dalmatian)

Poecilia sphenops

🐠Family Group
Bentos Tetra
Characins
Molly (Sailfin/Black/Dalmatian)
Livebearers
Temperament
Bentos Tetra
Peaceful (2/10)
Molly (Sailfin/Black/Dalmatian)
Mostly Peaceful (3/10)
Temperature
✓ Compatible
Bentos Tetra
23–28°C
Molly (Sailfin/Black/Dalmatian)
24–28°C
pH Range
✓ Compatible
Bentos Tetra
5.5–7.5
Molly (Sailfin/Black/Dalmatian)
7.5–8.5
Hardness (dGH)
✓ Compatible
Bentos Tetra
1–12
Molly (Sailfin/Black/Dalmatian)
12–30
Water Type
✓ Compatible
Bentos Tetra
Freshwater Only
Molly (Sailfin/Black/Dalmatian)
Brackish Tolerant
Flow Preference
✓ Compatible
Bentos Tetra
Low
Molly (Sailfin/Black/Dalmatian)
Moderate
Min Tank Volume
Combined: 75 L
Bentos Tetra
60 L
Molly (Sailfin/Black/Dalmatian)
75 L
Swimming Level
Shared: 1 zone
Bentos Tetra
MiddleBottom
Molly (Sailfin/Black/Dalmatian)
TopMiddle
🏷️Behavior Tags
Bentos Tetra
Hyperactive / Fast SwimmerShy / Slow Moving (Easily Stressed)
Molly (Sailfin/Black/Dalmatian)
Hyperactive / Fast SwimmerFry PredatorAggressive Eater (Starves shy fish)
Stocking calculator

Can your tank handle Bentos Tetra and Molly (Sailfin/Black/Dalmatian)?

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.

Bentos Tetra
Molly (Sailfin/Black/Dalmatian)
Test both in my tank

Behaviour & Temperament

Bentos Tetra is a peaceful species (2/10), while Molly (Sailfin/Black/Dalmatian) is generally mild-mannered (3/10). This modest difference means Molly (Sailfin/Black/Dalmatian) may occasionally assert dominance over Bentos Tetra.

Bentos Tetra and Molly (Sailfin/Black/Dalmatian) 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.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

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 7.5 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 12–12 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Bentos Tetra and Molly (Sailfin/Black/Dalmatian) together, plan for an aquarium of at least 75 litres with a minimum length of 60 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, Leaf Litter/Blackwater, Established Algae (Otocinclus). 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.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Bentos Tetra and Molly (Sailfin/Black/Dalmatian).

Show 17 more tank sizes

Diet & Feeding

Feeding time deserves special attention with this pairing. Molly (Sailfin/Black/Dalmatian) is an aggressive eater that may prevent Bentos Tetra from getting enough food.

Because Molly (Sailfin/Black/Dalmatian) is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Bentos Tetra receives an adequate share.

Frequently Asked Questions

Can Bentos Tetra and Molly (Sailfin/Black/Dalmatian) live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 75 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Bentos Tetra and Molly (Sailfin/Black/Dalmatian) need?

A minimum of 75 litres (tank length at least 60 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 Bentos Tetra and Molly (Sailfin/Black/Dalmatian) 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 Bentos Tetra or Molly (Sailfin/Black/Dalmatian) aggressive?

Bentos Tetra is peaceful (2/10) and Molly (Sailfin/Black/Dalmatian) is generally mild-mannered (3/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Bentos Tetra and Molly (Sailfin/Black/Dalmatian) need?

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


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