Can Freshwater Angelfish and Least Killifish (Heterandria) Live Together?
Freshwater Angelfish and Least Killifish (Heterandria) are not recommended as tank mates due to piscivorous fish will prey on nano-sized tank mates.. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.
At a Glance
Behaviour & Temperament
Freshwater Angelfish is a moderately assertive species (6/10), while Least Killifish (Heterandria) is peaceful (1/10). This notable difference means Freshwater Angelfish may occasionally assert dominance over Least Killifish (Heterandria).
Freshwater Angelfish and Least Killifish (Heterandria) both frequent the Middle (Open Water) and Top (Surface) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.
There is a critical concern: the Piscivore (Eats small/nano fish) behaviour of one fish directly conflicts with the Nano / Bite-sized (Predation Risk) trait of the other — piscivorous fish will prey on nano-sized tank mates..
Additional behavioural considerations to keep in mind: Shrimp eaters may also prey on very small nano fish.
Water Parameters
The safe temperature window for both species falls between 24°C and 27°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.
Both fish can tolerate a pH between 7 and 7.8. Maintaining a stable value within this band is more important than hitting an exact number.
For general hardness, the shared comfort zone is 5–15 dGH. Regular testing will ensure conditions stay within this range. An aquarium test kit is recommended for monitoring.
Tank Setup
To house Freshwater Angelfish and Least Killifish (Heterandria) together, plan for an aquarium of at least 180 litres with a minimum length of 90 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.
Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.
Specific environmental needs for this combination include: Plants - Densely covered, Driftwood (Digestion/Hiding), Plants - lighly 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.
Find the right tank equipment
Browse tanks, décor, and equipment suited for this setup.
Diet & Feeding
Feeding time deserves special attention with this pairing. Freshwater Angelfish is a known shrimp eater and may prey on small invertebrates or nano fish like Least Killifish (Heterandria).
Frequently Asked Questions
Can Freshwater Angelfish and Least Killifish (Heterandria) live together?▾
No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.
What size tank do Freshwater Angelfish and Least Killifish (Heterandria) need?▾
A minimum of 180 litres (tank length at least 90 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 Freshwater Angelfish and Least Killifish (Heterandria) together?▾
Keep the aquarium between 24°C and 27°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.
Are Freshwater Angelfish or Least Killifish (Heterandria) aggressive?▾
Freshwater Angelfish is moderately assertive (6/10) and Least Killifish (Heterandria) is peaceful (1/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.
What pH do Freshwater Angelfish and Least Killifish (Heterandria) need?▾
Both species overlap in the 7–7.8 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.
Will Freshwater Angelfish nip Least Killifish (Heterandria)'s fins?▾
Freshwater Angelfish is a known fin nipper. If Least Killifish (Heterandria) has long or flowing fins, there is a real risk of fin damage. Keeping Freshwater Angelfish in a larger group can help redirect nipping behaviour toward conspecifics.
How do I manage Freshwater Angelfish's territorial behaviour?▾
Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Freshwater Angelfish 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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