Aquarium for Beginners

Your first tank, in the order that keeps fish alive

Five stages. Most first tanks fail at the third, because it is the only one you cannot see happening.

Start: choose a tankAll 53 guides
  1. Choose a tank

    Day 1Size

    Buy a 20 gallon long

    Far more forgiving than a 5 or a 10, and $230 to set up on a tight budget, against $185.

  2. Buy the gear

    Day 1Equipment

    Filter, heater, test kit

    An AquaClear 30 and a 75 W Eheim Jäger for a 20 gallon done properly.

  3. Cycle it

    Weeks 1–6Water

    Grow the bacteria first

    Ready when 2 ppm ammonia reads 0 and 0 within 24 hours.

  4. Add fish

    Week 6+Stocking

    A few at a time

    Add four at a time, two weeks apart, and only once the cycle has finished.

  5. Keep a routine

    WeeklyUpkeep

    Change a quarter of the water

    25% once a week, and squeeze the filter sponge in old tank water once a month.

What we would buy

Our pick from each buying guide, chosen from maker specs and vet guidance, not hands-on tests. Each guide has the alternatives for other tanks.

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What a first tank costs

Every part, before fish and decor. The tight-budget column works; the other buys adjustability, and on the 20 a stand. Prices checked in September and October 2026.

TankTight budgetDone properly
10 gallonEvery item, priced$185$260plus about $70 for a stand
20 gallonEvery item, priced$230$400–$500with a stand

New guides

All 53 guides

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