The best tanks for goldfish

The tank is a purchase that is hard to undo, and one often got wrong, usually because a shop suggested something a goldfish would outgrow within a year. The tanks below are not the biggest you could buy. They are the sizes that match the fish, with a realistic interim option for readers who need to get a goldfish out of a bowl this week.

What to look for

Begin with the fish, not the furniture. Fancy goldfish reach 15–20 cm; single-tails reach 25–35 cm and larger in ponds. Our tank size guide explains the numbers we use across the site: 75–100 litres for a first fancy plus 40–50 for each additional fish, and 150–200 litres for a first single-tail plus 75–100 for each additional, with many keepers preferring 280 litres or a pond for adults. The tank size calculator turns that into a figure for your fish.

Shape matters almost as much as volume. Goldfish swim horizontally and use the floor of the tank, so a long, wide tank offers more usable space than a tall one holding the same water, and a larger surface for gas exchange. Cubes, columns and bowls waste volume on height.

Then consider what the tank does not include. Most tanks worth having are sold bare, so you will need a stand rated for the filled weight, a lid because goldfish jump, a filter rated above the tank’s volume, and lighting. Our guide to choosing a goldfish tank covers glass versus acrylic, and the setup guide covers everything that goes inside.

What to buy, by situation

Most people arrive at this page with one of six problems. This is the shortest straight answer to each.

Where you are	What to buy	The catch
A goldfish in a bowl, today	The largest long tank you can house this week, filtered	A 75-litre tank now beats a 200-litre tank in three months
One young fancy, planning properly	110–150 litres, long rather than tall	It will not look full for a year, and that is fine
Two or three fancies	200–300 litres	This is the size that stops being a compromise
A common, comet or shubunkin	280 litres minimum, or a tub, or a pond	Glass at this size needs a rated stand and a sound floor
Four or more fancies	300 litres and up, or two tanks	Two smaller tanks are easier to house than one large one
No room or budget for glass	A food-grade stock tank or mortar tub	You will see the fish from above, and that is the whole trade

The row that matters most is the first one. A fish in a bowl is in an emergency, and the tank that solves it is the one that can be set up this week rather than the one that would be ideal. Buy the interim tank, move the fish, and treat the proper tank as a separate project — the small one becomes a quarantine tank or a hospital tank afterwards, so nothing is wasted.

Where the tank comes from

The tank itself is the one part of a goldfish setup where the buying route changes the price more than the brand does.

Aquarium shops and chains sell standard sizes with matching stands and lids, which is worth something: an odd-sized tank is expensive to equip for the rest of its life. Chains run periodic promotions on bare glass tanks, and those promotions are often the cheapest way to buy new glass.

Second-hand is where the value is. Glass tanks last decades, people move house and give up the hobby constantly, and a large tank is difficult enough to transport that sellers price it to go. Standard sizes turn up most often, which is exactly what you want.

Farm and agricultural suppliers sell stock tanks and troughs in sizes glass simply does not reach at a sensible price, and builders’ merchants sell mortar tubs. Check the plastic is food-grade or explicitly aquarium-safe, and check whether it is UV-stabilised if it will sit anywhere bright.

What to avoid buying blind is an unusual footprint. A tank that no standard lid, stand or hood fits means paying for custom versions of all three, and the saving disappears immediately.

What the tank purchase actually includes

Very few tanks are a complete purchase, and the shortfall catches people out after the money is spent. These are the day-one items.

• The stand, rated for the filled weight, supporting the whole base rather than the corners, and level in both directions. Tank placement and floor loading covers what the floor underneath has to do.
• A lid. Goldfish jump, particularly in the first weeks in a new tank, and a lid also slows evaporation.
• A filter rated well above the volume. The filter buying guide covers how to read those ratings, which are not written with goldfish in mind.
• Dechlorinator, before a drop of tap water goes in.
• A liquid test kit. Not optional, because cycling the tank is invisible without one.

What can wait: substrate, plants, decor, a light, and a second filter. None of them keeps a fish alive in week one, and a bare tank with good water is a better home than a decorated one with a filter that cannot keep up.

What most goldfish never need at all: a heater. Goldfish are coldwater fish, and a room that is comfortable for people is usually comfortable for them.

What keeping goldfish costs sets out the proportions over a year, and the short version is that the tank is rarely the largest line — the cost guide has the rest.

Buying second-hand, in order

A checklist aimed at the transaction rather than the theory.

1. Ask how old it is and whether it has been drained for long. Silicone that has been dry for years sometimes fails when refilled.
2. Look along the seams for cloudiness, bubbles or lifting edges. Neat, clear, evenly laid silicone is a good sign; a bead that has been patched over is not.
3. Check the braces. A central cross-brace on a long tank is structural. Cracked, removed, or previously repaired means walk away.
4. On acrylic, look for crazing — fine surface cracks, usually around the corners or near old fittings.
5. Buy the tank, not the kit. Old filters, gravel and decorations are rarely worth transporting, and a filter that has been dry carries no useful bacteria anyway.
6. Test it outdoors before it enters the house. Fill it on a flat surface, leave it a full day, and look underneath. This is the step people skip and the only one that actually proves anything.
7. Then clean it with water and a blade, never detergent.

Tubs, troughs and the non-glass options

Underrated, and for large single-tails frequently the right answer.

What works: food-grade stock tanks, mortar tubs, preformed pond liners used indoors, and large plastic troughs. They give volume that glass cannot match for the money, they need no stand because they sit on the floor, and many have a drain plug that turns a water change into an easy job.

What they cost you is the side view. You look down at the fish rather than through at them, which is how goldfish were kept and bred for most of their history and is genuinely a good way to see a ranchu or a tosakin, but it is not what most people picture when they imagine a tank.

What to check before buying: that the plastic is food-grade or explicitly aquarium-safe, that it has no previous chemical use, and that it is rigid enough not to bow when filled. And cover it, because a tub in a room is as jumpable as a tank.

The same tub can go outside for the summer, which the tub and patio pond guide covers. Goldfish ponds covers the full-size outdoor version of the argument, and it is worth reading before buying any tank for a common or comet, because for those fish a pond is often the right destination.

Our picks explained

Aqueon Standard Glass 75 Gallon: best overall

The standard 75 gallon, about 122 × 46 × 53 cm, is the size at which a small group of fancies or a pair of single-tails stops being a compromise. Nitrate builds slowly enough that weekly changes keep up, the length gives single-tails room to swim, and every stand, lid and filter comes in this size. It is heavy, at roughly 380 kg filled, but it saves the upgrade most keepers make anyway.

Aqueon 40 Gallon Breeder: best for fancy goldfish

A breeder tank is wide and low: a 40-gallon breeder is about 91 × 46 × 41 cm, about 170 litres by those dimensions and 150 litres nominal. That footprint gives a pair of fantails or orandas far more swimming room than a taller 150-litre tank, and the low height makes cleaning easy. It ships bare, the 46 cm depth means a bookshelf will not do, and it is not a long-term home for single-tails.

Rubbermaid 100 Gallon Stock Tank: best for single-tails on a budget

Adult commons and comets need pond-scale volume more than a pretty tank, and a stock tank delivers about 380 litres for a fraction of the cost of glass. It is very tough, needs no stand, and its drain plug makes big water changes simple. You view the fish from above; add a large sponge or canister filter and a net cover, and read our ponds guide for the rest.

Aqueon 20 Gallon Long: best interim upgrade

We would not call 75 litres a permanent home for an adult fancy. But someone with a goldfish in a bowl needs a filtered tank they can afford and house now, and a long 20 gallon with a sponge or hang-on-back filter changes that fish’s life immediately. Water quality swings faster in a small volume, and plan the move to 100 litres or more as the fish grows.

Juwel Rio 240 LED: best complete kit

European readers can buy a good-looking 240-litre tank with matched LED lighting, a heater and a corner internal filter, and simply fill it. The catch is the filter: its turnover is at the low end for goldfish and its box takes a corner of the swimming space, so treat it as half your filtration and add a sponge filter or hang-on-back.

What we would skip

Bowls, however large; our guide to whether goldfish can live in a bowl explains why. Tiny starter kits under 40 litres with a goldfish on the box. Tall columns and cubes, which waste volume on height. Any tank whose price depends on an included filter sized for tropical fish. And, for single-tails, anything under 150 litres that is not explicitly a stopgap.

Buy the largest standard, long tank you can house and afford, and buy it once. The fish will grow into it faster than you expect — how big goldfish get is the page that convinces most people to go one size up.