1. Choose the tank and its spot
Pick the largest tank your space and budget allow — bigger volumes are more stable and more forgiving of beginner mistakes. Place it on furniture rated for the weight (water is 1 kg per litre, so a 100 L tank plus substrate is well over 120 kg), away from direct sunlight and draughts, and near a power socket. Once it is filled, you cannot move it, so decide carefully. Browse options in our aquariums hub.
2. Rinse and add substrate
Rinse gravel or sand until the water runs clear (aqua soils are the exception — never rinse those). Add a sloped layer, deeper at the back, for depth and easy planting. For a planted tank an active aqua soil feeds roots and buffers pH; for a fish-only or shrimp tank, inert sand or fine gravel is cheaper and easier to keep clean. Our substrate guide and best planted substrate round-up cover the choice in detail.
3. Add hardscape
Position rocks and driftwood before you add water — it is far easier while the tank is dry. Build your layout around one focal point rather than spreading pieces evenly; odd numbers and a clear "heavy" side tend to look natural. Soak driftwood beforehand or weigh it down, as fresh wood floats and can leach tannins that tint the water.
4. Install the filter and heater
- Filter: aim for roughly 4× your tank volume in turnover per hour — a 100 L tank wants around 400 L/h. Round up rather than down. See our filters hub and best external filter pick.
- Heater: budget about 1 watt per litre in a heated room, a little more in a cold one. Place it near the filter flow so warmed water circulates evenly. See the heaters hub.
- Lighting: a timer set to a 6–8 hour photoperiod keeps plants happy and algae in check. See lighting.
5. Fill with water
Pour onto a plate or a bag laid on the substrate so you do not blast a crater into it. Fill with dechlorinated water, or add a dechlorinator as you fill to neutralise chlorine and chloramine from tap water. Only switch the heater on once it is fully submerged, and prime the filter before powering it up.
6. Plant it
Plant now, while the water is clear and you can see what you are doing. Start with hardy, forgiving species — Java fern, Anubias, Cryptocoryne and stem plants — that tolerate a new tank. Root-feeders go in the substrate; Java fern and Anubias attach to hardscape and must not be buried. Our aquascaping for beginners guide walks through planting technique.
7. Cycle before adding fish
The hardware is running, but the tank is not ready for life. You now need to grow beneficial bacteria to process fish waste — the nitrogen cycle. Run a fishless cycle for a few weeks, testing with a liquid test kit until ammonia and nitrite read zero. Only then, after a water change, add your first few fish gradually. Patience here is what separates a thriving tank from a stressful one.