Why Tank Size Matters More Than You Think

The single most common piece of advice you will hear from experienced fishkeepers is also the one beginners most often ignore: buy a bigger tank than you think you need. A 10-litre bowl looks manageable and cheap. It is also one of the hardest environments to keep stable. Water temperature swings faster, toxins build up quicker, and there is almost no room for error.

A 60–100 litre tank is a far kinder starting point. You still need to learn the basics, but the water chemistry changes more slowly, which gives you time to notice problems before they become emergencies.

What Equipment You Actually Need

The essentials are fewer than most shop displays suggest:

  • Filter — the single most important piece of kit. It houses the bacteria that break down fish waste. Buy one rated for slightly more than your tank volume.
  • Heater — for tropical fish, you need the water between 24–27 °C. Get a reliable brand with an external thermometer to double-check its reading.
  • Lighting — a basic LED strip is fine for fish-only tanks. You do not need anything special unless you plan to grow live plants.
  • Lid — fish jump. Even species you would not expect to.
  • Substrate — plain gravel or aquarium sand both work. Rinse it thoroughly before adding it; the water will still go cloudy, but it settles.

You do not need a protein skimmer (that is marine), UV sterilisers, or CO2 injection at this stage. Save that money.

Setting Up the Tank Step by Step

Rinse everything — tank, filter media, substrate — with plain water. No soap, ever. Place the tank on a solid, level surface that can bear the weight (a full 100-litre tank weighs over 100 kg including substrate and decor).

Fill with dechlorinated tap water. Tap water contains chlorine or chloramine, both of which are harmless to humans but toxic to the beneficial bacteria you will be cultivating. A bottle of liquid dechlorinator costs very little and you need just a few drops per litre.

Add your filter, heater, and any decor. Turn everything on and let it run for 24–48 hours before adding any fish — and even then, the tank is not ready unless it has been cycled (see the nitrogen cycle guide).

A Note on Decor

Fish need places to hide. Bare tanks stress most species, which suppresses their immune systems. A few pieces of driftwood, smooth rocks, or artificial caves make a real difference. Just make sure anything you add is aquarium-safe; garden stones and painted ornaments can leach chemicals or alter your water’s pH.

Live plants are genuinely helpful — they absorb some nitrogen waste and oxygenate the water — but plastic ones are fine if you are not ready for plant care yet.

The golden rule for setup: patience before fish. A properly prepared tank is the foundation everything else depends on.