I have set up tanks that crashed in week two and tanks that are still stable years later. The difference is almost never luck. This guide walks the livebearer tank from empty glass to stable, livable water without the usual week-two crash.
What you need
- A 20-gallon tank and a stand rated for the weight (~80 kg when full).
- Filter rated for at least 80 L/h.
- Heater (if tropical): 83 W.
- Substrate: 5 cm deep.
- Live plants and a light on a 8-hour timer.
Step by step
- Rinse substrate, add it, and hardscape before filling.
- Fill slowly to avoid clouding; start the filter and heater.
- Cycle the tank — see our iwagumi aquascape guide guide — for 33 days until ammonia and nitrite read 0 ppm.
- Test water, then add a small group of hardy fish; build up slowly.
Common mistakes
Adding fish during the first week, skipping the cycle, and skipping water tests are the big three. A 38% water change weekly, using a solid magnetic algae cleaner for a small tank, prevents most problems before they start.
Next steps
Once stable, layer in more plants and a few peaceful tank mates. Keep a log of parameters; a tank you measure is a tank you can trust.
Beginner shortcuts
Skip the gadgets: a 20-gallon tank, a cycled filter, a heater, and live plants are enough. Cycle for 16 days, test the water, then add a small hardy group and change about 25% of the water weekly.
