Can Black Ruby Barb and Freshwater Shark (Wallago) Live Together?

Possible with Caution

Keeping Black Ruby Barb and Freshwater Shark (Wallago) together is possible but requires caution due to differing aggression levels. Provide a spacious tank of at least 5500 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Black Ruby Barb

Pethia nigrofasciata

Freshwater Shark (Wallago)

Wallago attu

🐠Family Group
Black Ruby Barb
Cyprinids
Freshwater Shark (Wallago)
Catfish
Temperament
Black Ruby Barb
Mostly Peaceful (3/10)
Freshwater Shark (Wallago)
Highly Aggressive (10/10)
Temperature
✓ Compatible
Black Ruby Barb
20–26°C
Freshwater Shark (Wallago)
19–29°C
pH Range
✓ Compatible
Black Ruby Barb
5.5–7.5
Freshwater Shark (Wallago)
6–7.6
Hardness (dGH)
✓ Compatible
Black Ruby Barb
2–15
Freshwater Shark (Wallago)
1–20
Water Type
✓ Compatible
Black Ruby Barb
Freshwater Only
Freshwater Shark (Wallago)
Freshwater Only
Flow Preference
✓ Compatible
Black Ruby Barb
Moderate
Freshwater Shark (Wallago)
Moderate
Min Tank Volume
Combined: 5500 L
Black Ruby Barb
80 L
Freshwater Shark (Wallago)
5500 L
Swimming Level
Shared: 2 zones
Black Ruby Barb
MiddleBottom
Freshwater Shark (Wallago)
MiddleBottom
🏷️Behavior Tags
Black Ruby Barb
Hyperactive / Fast SwimmerFry PredatorAggressive Eater (Starves shy fish)
Freshwater Shark (Wallago)
Piscivore (Eats small/nano fish)Generally AggressiveAggressive to same species/look-alikesJumper (Lid Required)Hyperactive / Fast Swimmer
Stocking calculator

Can your tank handle Black Ruby Barb and Freshwater Shark (Wallago)?

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.

Black Ruby Barb
Freshwater Shark (Wallago)
Test both in my tank

Behaviour & Temperament

Black Ruby Barb is a generally mild-mannered species (3/10), while Freshwater Shark (Wallago) is highly aggressive (10/10). This notable difference means Freshwater Shark (Wallago) may occasionally assert dominance over Black Ruby Barb.

Large aggression gap (7 points) between Black Ruby Barb and Freshwater Shark (Wallago) increases stress risk for the more peaceful fish.

Black Ruby Barb and Freshwater Shark (Wallago) both frequent the Middle (Open Water) and Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Worth noting: Freshwater Shark (Wallago) 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 20°C and 26°C. Aim for the midpoint of this range (around 23.0°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 2–15 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Black Ruby Barb and Freshwater Shark (Wallago) together, plan for an aquarium of at least 5500 litres with a minimum length of 300 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, Driftwood (Digestion/Hiding), Sand (Sifters), Smooth Gravel (Sensitive Barbels). 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.

Frequently Asked Questions

Can Black Ruby Barb and Freshwater Shark (Wallago) live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 5500 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Black Ruby Barb and Freshwater Shark (Wallago) need?

A minimum of 5500 litres (tank length at least 300 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 Black Ruby Barb and Freshwater Shark (Wallago) together?

Keep the aquarium between 20°C and 26°C. A target of around 23.0°C sits comfortably within both species' preferred ranges.

Are Black Ruby Barb or Freshwater Shark (Wallago) aggressive?

Black Ruby Barb is generally mild-mannered (3/10) and Freshwater Shark (Wallago) is highly aggressive (10/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Black Ruby Barb and Freshwater Shark (Wallago) 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.


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