🐠Killifish: gear and buying guides

Killifish, such as Aphyosemion australe, are small, brilliantly colored fish often content with 20 to 50 L tanks. Many prefer soft, slightly acidic and rather cool water, between 20 and 24 °C, with subdued lighting. Outstanding jumpers, they demand a lid with no gaps at all; some annual species have naturally short lifespans.

Profile : 4 to 6 cm as an adult depending on the species, 20 to 50 L depending on the species, water between 20 and 24 °C.

Species profile

Lifespan

1 to 3 years

Adult size

5 cm

Minimum tank

20 L

Water temperature

20 to 24 °C

pH

6 to 7

Temperament

A lively, colorful little surface fish, often kept species-only with one male and two or three females.

Health watch

velvet (oodinium) in unstable water · sensitivity to elevated nitrates

🩺 Our hygiene and health advice stays general: it never substitutes for an examination by a veterinarian, the only person qualified to advise on your animal.

Killifish gear, family by family

• 🍖 Food

  A surface carnivore that prefers live and frozen foods: brine shrimp, daphnia, grindal worms. Many killifish snub dry flakes, so keep a stock of frozen food.

• 🧴 Care & grooming

  Soft, slightly acidic water without elevated nitrates, often softened with RO water. Constantly warm temperatures noticeably shorten its lifespan.

• 🎾 Toys & enrichment

  Floating plants, Java moss and a dark substrate show off its colors and reassure it. A synthetic-yarn spawning mop encourages breeding behavior.

• 🏠 Bedding & habitat

  A 20 to 50 L tank depending on the species, gently filtered, often kept species-only with one male and two or three females. A gap-free lid is the number one safety point.

• 🧳 Travel & safety

  It jumps the moment the bag opens: handle it above a closed surface and transfer carefully. Slow 30 to 45 minute acclimation, especially into harder water.

• 🧰 Accessories

  A sponge filter, a snug lid, peat or catappa leaves for acidifying and a spawning mop. A small budget of around 60 to 120 euros for a complete species tank.

Guides to read

• Community aquarium or species-only tank: which is right for a first setup?Bedding & habitat

  Community aquarium or species-only tank: pros, cohabitation risks and advice for choosing how to set up your first aquarium.

• Best easy aquarium plants without CO2 for beginnersToys & enrichment

  Which aquarium plants can you choose without CO2 injection? A selection of hardy, easy plants for a beginner's planted tank.

• Budget for a first brackish water aquarium: the real cost to get startedBedding & habitat

  How much does a first brackish water aquarium cost? Tank, filtration, salt and salinity monitoring, budgeted item by item.

• Changing filter media too often: the mistake that wrecks your aquarium's cycleCare & grooming

  Why you should never replace all your filter media at once: nitrifying bacteria, replacement frequency and the right habits.

• Restarting a neglected aquarium: a step-by-step guideCare & grooming

  How do you restart an aquarium that's been left neglected without endangering the fish? Steps, water changes and mistakes to avoid.

• GH, KH and pH: understanding and adjusting aquarium water hardnessCare & grooming

  GH, KH, pH: what do these three readings actually measure, and how do you adjust aquarium water hardness without stressing the fish?

• Upgrading to a bigger aquarium: moving your fish without the stressBedding & habitat

  How do you upgrade to a bigger aquarium without breaking the biological cycle or stressing your fish? Steps and mistakes to avoid.

• Aquarium electrical safety: GFCI protection and good habitsTravel & safety

  Heater, filter, lighting near the water: what electrical precautions keep an aquarium safe for fish and people?