What do I actually need to start?

A tank (with a lid), a filter, a heater (for tropical fish), a thermometer, a water test kit, water conditioner (dechlorinator), substrate, and a few plants and hides. Not on the list: fish — those come weeks later, after the tank is cycled.

How long before I can add fish?

Plan on a few weeks. You cycle the empty tank first (usually 2–6 weeks) so the beneficial bacteria are established before any fish arrive. Seeding the filter with media from an established tank can shorten this considerably. The wait is the single biggest favour you can do your first fish.

What size tank should a beginner get?

Bigger than you'd think — most beginners do best starting around 60–75 litres (15–20 US gal). More water is more stable and more forgiving of mistakes. Avoid bowls and tiny nanos for a first tank; they're actually the hardest to keep.

Do I need live plants?

You don't have to have them, but they help a lot: live plants take up ammonia and nitrate, compete with algae, and give fish cover. Easy starters (java fern, anubias, floating plants) are hard to kill and make a new tank more stable. Silk or plastic plants are fine too — just avoid anything sharp near long-finned fish.

How to set up your first aquarium: the honest beginner's path (in the right order)

Q: What fish should I start with?

Peaceful, hardy species suited to your water and tank size — and added to a cycled tank, slowly. Good beginner options include guppies, platies, harlequin rasboras, zebra danios, corydoras (in groups), and a betta as a solo centrepiece. Check each species' care guide for its needs first.

The 30-second version. Do it in this order: choose a reasonable-sized tank (not a bowl, not a nano — around 60–75 L is a kind starting point) → add a filter, heater and a lid → fill and dechlorinate → cycle the tank before any fish (a few weeks) → add fish slowly, checking each species first → settle into a weekly water change routine. The patience up front is what makes it easy forever after.

Welcome, tankmate. If you’re reading this before you’ve bought anything, you’re already ahead of most people — because the biggest beginner mistakes happen in the order things are done. Do the steps in the right sequence and fishkeeping is calm and forgiving. Do them backwards (fish first, water knowledge later) and it’s stressful for you and dangerous for the fish.

Here’s the honest path.

Step 1 — Choose the tank (bigger than you think)

Skip the bowl and skip the tiny “starter” nano. Counter-intuitively, a bigger tank is easier for a beginner — more water is more stable and forgives mistakes. Around 60–75 litres (15–20 US gal) is a lovely first size. Then let the fish you want set the final size: check their adult size and minimum tank first. Full reasoning in how big a tank does my fish need?

Get a lid too — lots of fish jump.

Step 2 — Add the equipment

Filter — the living heart of the tank. A sponge or hang-on-back filter is ideal for a first tank; size it to move ~4–6× the tank volume per hour. See aquarium filters explained.
Heater + thermometer — for tropical fish, a thermostatically-controlled heater to hold a steady temperature. (Coldwater fish like goldfish don’t need one.)
Substrate, plants and hides — sand or gravel, a few easy live plants (java fern, anubias, floating plants) or silk plants, and some cover so fish feel secure.
A water test kit — ideally a liquid kit. This is how you’ll “see” the invisible water chemistry.

Step 3 — Fill it and dechlorinate

Rinse substrate before it goes in (to avoid cloudy water from dust), fill the tank, add water conditioner to neutralise the chlorine/chloramine in tap water, and get the filter and heater running. A little early cloudiness is normal and settles.

Step 4 — Cycle the tank BEFORE any fish

This is the step everyone skips and the one that matters most. A brand-new tank has no bacteria to process fish waste, so fish added now are slowly poisoned. Instead, cycle the empty tank — grow the bacteria first — over a few weeks, then add fish to safe water.

This deserves its own read, so go do it now: the nitrogen cycle (and the fishless-cycling method). Seeding your filter with media from an established tank speeds it up dramatically.

Step 5 — Add fish slowly

Once the tank is cycled (it can clear a dose of ammonia to zero ammonia and zero nitrite in 24 hours):

Choose peaceful, hardy species suited to your water and size — browse the care guides and read each one first (adult size, group needs, temperament).
Add a few at a time, not all at once — a sudden bioload spike outpaces your bacteria.
Acclimatise gently (float and mix tank water into the bag before releasing), and don’t feed heavily in the first days.

Good first fish include guppies, platies, harlequin rasboras, zebra danios, corydoras (in a group of 6+), or a betta as a solo centrepiece.

Step 6 — Settle into the routine

The hard part is over; now it’s maintenance:

A weekly water change (~25–30% for a normal community tank) — the single best habit there is.
Feed lightly — only what fish finish in a minute or two.
Keep an eye on the water with occasional tests, and manage algae with light and nutrient balance.
Don’t rinse your filter in tap water, and never turn it off.

That’s it. Set it up in this order, be patient before the fish, and you’ll skip almost every beginner disaster. Get the water right, and the fish look after themselves.

Sources & further reading

RSPCA Knowledgebase — Caring for goldfish — tank sizing, why bowls are unsuitable, and new-tank water-testing guidance.
INJAF — The Nitrogen Cycle and the Fishless Cycle — why (and how) to cycle a tank before adding fish.
Aquarium Store Depot — How Many Fish Per Gallon? — why bigger, lightly-stocked tanks are easier and more stable for beginners.