The Killifish tank: 20 L, hardware and start-up
Killifish : 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.
In our shop, for this use: Hollow moss-effect resin log for aquariums (€20.90) · the whole shop
Outside our shipping area? The downloadable practical guide: Beginner axolotl: aquarium and care (€19)
In short: 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. A lively, colorful little surface fish, often kept species-only with one male and two or three females. A formidable jumper requiring a gap-free lid; its lifespan varies greatly by species, often only 1 to 3 years.
20 litres minimum: why that number
For a Killifish reaching 5 cm as an adult, plan 20 real litres — and remember a big tank is more STABLE, hence easier, than a small one: parameters drift slowly, leaving time to correct. This volume suits a sturdy standard cabinet — just verify perfect levelness.
Hardware: filter, heater, lighting
On hardware: a filter cycling the volume three to five times an hour, a heater around 1 W per litre set to 20 to 24°C, backed by an independent thermometer — built-in thermostats sometimes lie, and lighting on a timer at 8 to 10 hours a day: any longer and the algae win.
Substrate, plants and start-up
Nutrient substrate under fine sand or quartz, robust plants (anubias, vallisneria, Java moss) and wood to structure the territory. Then patience: a complete nitrogen cycle (3 to 4 weeks, nitrites back to zero) before the first Killifish — the step every hurried beginner pays for dearly.
Frequently asked questions
What tank size for a Killifish?
A real 20 litres minimum — below that, parameters drift too fast to catch.
Does a Killifish need a heater?
Yes, about 1 W per litre set to 20 to 24°C, with an independent thermometer double-checking the thermostat.
The guides that apply to you
- What Size Aquarium Should You Start With? The Real Number (and the Fishbowl Myth)
60, 100 or 120 litres? Find out what aquarium size to choose for a stress-free start, why the fishbowl should be banned from your plans, and what budget to expect.
- Shrimp and Betta Cohabitation: Good Idea or Guaranteed Risk?
The betta is a natural predator of small shrimp. When cohabitation can actually work, and why it usually fails.
- Guppy Reproduction: Why the Population Explodes and How to Manage It
Guppies breed very fast with no intervention needed. Why this rapid reproductive strategy exists, and how to avoid overpopulation in a community tank.
- Glass or acrylic: which material should you choose for your aquarium?
Glass or acrylic (plexiglass): weight, scratch resistance, clarity and price — the real criteria for choosing your tank's material.