Can Gardner's Killifish and Largemouth Bass Live Together?

Possible with Caution

Keeping Gardner's Killifish and Largemouth Bass together is possible but requires caution due to differing aggression levels. Provide a spacious tank of at least 1135 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

Largemouth Bass

Micropterus salmoides

🐠Family Group
Gardner's Killifish
Killifish
Largemouth Bass
Other
Temperament
Gardner's Killifish
Mostly Peaceful (4/10)
Largemouth Bass
Aggressive (8/10)
Temperature
✓ Compatible
Gardner's Killifish
20–26°C
Largemouth Bass
10–28°C
pH Range
✓ Compatible
Gardner's Killifish
6–7.5
Largemouth Bass
6.5–8.5
Hardness (dGH)
✓ Compatible
Gardner's Killifish
4–10
Largemouth Bass
5–25
Water Type
✓ Compatible
Gardner's Killifish
Freshwater Only
Largemouth Bass
Freshwater Only
Flow Preference
✓ Compatible
Gardner's Killifish
Low
Largemouth Bass
Moderate
Min Tank Volume
Combined: 1135 L
Gardner's Killifish
38 L
Largemouth Bass
1135 L
Swimming Level
Shared: 2 zones
Gardner's Killifish
TopMiddle
Largemouth Bass
TopMiddle
🏷️Behavior Tags
Gardner's Killifish
Jumper (Lid Required)Fry PredatorShrimp EaterHyperactive / Fast Swimmer
Largemouth Bass
Piscivore (Eats small/nano fish)Shrimp EaterFry PredatorHyperactive / Fast SwimmerJumper (Lid Required)Aggressive Eater (Starves shy fish)
Stocking calculator

Can your tank handle Gardner's Killifish and Largemouth Bass?

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.

Gardner's Killifish
Largemouth Bass
Test both in my tank

Behaviour & Temperament

Gardner's Killifish is a generally mild-mannered species (4/10), while Largemouth Bass is semi-aggressive (8/10). This notable difference means Largemouth Bass may occasionally assert dominance over Gardner's Killifish.

Gardner's Killifish and Largemouth Bass both frequent the Top (Surface) and 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.

Worth noting: Gardner's Killifish 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 6.5 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 5–10 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Gardner's Killifish and Largemouth Bass together, plan for an aquarium of at least 1135 litres with a minimum length of 240 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, Plants - Floating, Plants - lighly covered, Driftwood (Digestion/Hiding). 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.

Frequently Asked Questions

Can Gardner's Killifish and Largemouth Bass live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 1135 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Gardner's Killifish and Largemouth Bass need?

A minimum of 1135 litres (tank length at least 240 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 Largemouth Bass 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 Largemouth Bass aggressive?

Gardner's Killifish is generally mild-mannered (4/10) and Largemouth Bass is semi-aggressive (8/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Gardner's Killifish and Largemouth Bass need?

Both species overlap in the 6.5–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.


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