Can Florida Flagfish and Golden Wonder Killifish Live Together?

🟡Possible with Caution

Keeping Florida Flagfish and Golden Wonder Killifish together is possible but requires caution, though some care is needed. Provide a spacious tank of at least 90 litres with plenty of hiding spots to reduce stress. Monitor behaviour closely, especially during the first few weeks.


At a Glance

Florida Flagfish

Jordanella floridae

Golden Wonder Killifish

Aplocheilus lineatus

🐟Family Group
Florida Flagfish
Killifish
Golden Wonder Killifish
Killifish
Temperament
Florida Flagfish
Semi-Aggressive (5/10)
Golden Wonder Killifish
Semi-Aggressive (6/10)
Temperature
✓ Compatible
Florida Flagfish
18–26°C
Golden Wonder Killifish
22–28°C
pH Range
✓ Compatible
Florida Flagfish
6.5–8.5
Golden Wonder Killifish
6–7.5
Hardness (dGH)
✓ Compatible
Florida Flagfish
10–25
Golden Wonder Killifish
5–20
Water Type
✓ Compatible
Florida Flagfish
Brackish Tolerant
Golden Wonder Killifish
Brackish Tolerant
Flow Preference
✓ Compatible
Florida Flagfish
Low
Golden Wonder Killifish
Low
Min Tank Volume
Combined: 90 L
Florida Flagfish
75 L
Golden Wonder Killifish
75 L
Swimming Level
✓ Different zones
Florida Flagfish
MiddleBottom
Golden Wonder Killifish
Top
🏷️Behavior Tags
Florida Flagfish
Fin NipperAggressive to same species/look-alikesHyperactive / Fast SwimmerTerritorial (Defends specific area)
Golden Wonder Killifish
Piscivore (Eats small/nano fish)Jumper (Lid Required)Shrimp EaterFry PredatorHyperactive / Fast Swimmer

Behaviour & Temperament

Florida Flagfish is a moderately assertive species (5/10), while Golden Wonder Killifish is moderately assertive (6/10). This modest difference means Golden Wonder Killifish may occasionally assert dominance over Florida Flagfish.

In terms of spatial distribution, Florida Flagfish prefers the Middle (Open Water) and Bottom (Substrate) zones, whereas Golden Wonder Killifish occupies the Top (Surface) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Worth noting: Golden Wonder Killifish is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: Provide a significantly larger tank (at least 50% more volume than the minimum) to allow both Florida Flagfish and Golden Wonder Killifish to establish separate territories. Add plenty of line-of-sight breaks using driftwood, rocks, and dense planting to reduce territorial confrontations. Keep fin nippers in larger groups to distribute nipping behaviour among conspecifics rather than tank mates.

Water Parameters

The safe temperature window for both species falls between 22°C and 26°C. Aim for the midpoint of this range (around 24.0°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 10–20 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Florida Flagfish and Golden Wonder Killifish together, plan for an aquarium of at least 90 litres with a minimum length of 60 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: Established Algae (Otocinclus), Plants - Densely covered, Plants - Floating. 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 Florida Flagfish and Golden Wonder Killifish live together?

They can coexist, but the pairing requires careful monitoring. Provide ample space (at least 90 litres), plenty of hiding spots, and watch for signs of stress or aggression.

What size tank do Florida Flagfish and Golden Wonder Killifish need?

A minimum of 90 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 Florida Flagfish and Golden Wonder Killifish together?

Keep the aquarium between 22°C and 26°C. A target of around 24.0°C sits comfortably within both species' preferred ranges.

Are Florida Flagfish or Golden Wonder Killifish aggressive?

Florida Flagfish is moderately assertive (5/10) and Golden Wonder Killifish is moderately assertive (6/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Florida Flagfish and Golden Wonder Killifish 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.

Will Florida Flagfish nip Golden Wonder Killifish's fins?

Florida Flagfish is a known fin nipper. If Golden Wonder Killifish has long or flowing fins, there is a real risk of fin damage. Keeping Florida Flagfish in a larger group can help redirect nipping behaviour toward conspecifics.

How do I manage Florida Flagfish's territorial behaviour?

Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Florida Flagfish space to claim a territory without encroaching on the other fish's area. Adding décor that divides the tank into distinct zones works especially well.


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