Can Gardner's Killifish and Red-Tail Catfish Live Together?

🟡Possible with Caution

Keeping Gardner's Killifish and Red-Tail Catfish together is possible but requires caution, though some care is needed. Provide a spacious tank of at least 4560 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Gardner's Killifish

Fundulopanchax gardneri

Red-Tail Catfish

Phractocephalus hemioliopterus

🐠Family Group
Gardner's Killifish
Killifish
Red-Tail Catfish
Catfish
Temperament
Gardner's Killifish
Mostly Peaceful (4/10)
Red-Tail Catfish
Aggressive (7/10)
Temperature
✓ Compatible
Gardner's Killifish
20–26°C
Red-Tail Catfish
20–28°C
pH Range
✓ Compatible
Gardner's Killifish
6–7.5
Red-Tail Catfish
6–7.5
Hardness (dGH)
✓ Compatible
Gardner's Killifish
4–10
Red-Tail Catfish
3–15
Water Type
✓ Compatible
Gardner's Killifish
Freshwater Only
Red-Tail Catfish
Freshwater Only
Flow Preference
✓ Compatible
Gardner's Killifish
Low
Red-Tail Catfish
Moderate
Min Tank Volume
Combined: 4560 L
Gardner's Killifish
38 L
Red-Tail Catfish
3800 L
Swimming Level
✓ Different zones
Gardner's Killifish
TopMiddle
Red-Tail Catfish
Bottom
🏷️Behavior Tags
Gardner's Killifish
Jumper (Lid Required)Fry PredatorShrimp EaterHyperactive / Fast Swimmer
Red-Tail Catfish
Piscivore (Eats small/nano fish)Plant DestroyerDigger (Disturbs Substrate)Nocturnal

Behaviour & Temperament

Gardner's Killifish is a generally mild-mannered species (4/10), while Red-Tail Catfish is semi-aggressive (7/10). This modest difference means Red-Tail Catfish may occasionally assert dominance over Gardner's Killifish.

In terms of spatial distribution, Gardner's Killifish prefers the Top (Surface) and Middle (Open Water) zones, whereas Red-Tail Catfish 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: Red-Tail Catfish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Gardner's Killifish is a known jumper, so a tight-fitting lid is essential.

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 4–10 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.

Tank Setup

To house Gardner's Killifish and Red-Tail Catfish together, plan for an aquarium of at least 4560 litres with a minimum length of 300 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, Plants - Floating, Plants - lighly covered, Sand (Sifters), Smooth Gravel (Sensitive Barbels), Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Red-Tail Catfish is a plant destroyer, which conflicts with Gardner's Killifish's requirement for live plants. Compromise where possible or prioritise the more critical need.

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

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Frequently Asked Questions

Can Gardner's Killifish and Red-Tail Catfish live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 4560 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Gardner's Killifish and Red-Tail Catfish need?

A minimum of 4560 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 Gardner's Killifish and Red-Tail Catfish 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 Gardner's Killifish or Red-Tail Catfish aggressive?

Gardner's Killifish is generally mild-mannered (4/10) and Red-Tail Catfish is semi-aggressive (7/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Gardner's Killifish and Red-Tail Catfish 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 Red-Tail Catfish being nocturnal affect compatibility?

Red-Tail Catfish 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 Red-Tail Catfish during evening hours.


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