TankBud

Goldfish

Goldfish are hardy coldwater fish that grow bigger and messier than most people expect, so they need far more filtration and space than a bowl. Single-tail types like commons and comets are fast and grow large, while the round fancy varieties such as oranda, ryukin and ranchu are slower and more delicate. Each profile lists adult size, tank size and the care a variety needs.

At a glance

Tank size
20–119 gal
20 gal (75 L) to 119 gal (450 L); half the list needs 25 gal (95 L) or more
Temperature
61–75°F
16–24°C, most of the list
pH
6.5–8.0
Most of the list
Difficulty
5 easy
6 medium · 2 difficult

2 species and 12 varieties

Start here

Six goldfish to know

The common goldfish is marked beginner at 9.8 inches (25 cm) for 50 gallons (190 liters) and takes 39–75°F (4–24°C), a pond fish that fits a large tank. The fantail is the first fancy goldfish, marked easy at 7.1 inches (18 cm) for 20 gallons (75 liters) with a double tail and an egg-shaped body. The oranda carries a raspberry growth on its head and reaches 9.8 inches (25 cm) for 30 gallons (114 liters), marked medium. The black moor is the fantail with telescope eyes, 7.9 inches (20 cm) for 25 gallons (95 liters). The ryukin is the deep-bodied one with a high shoulder, the same size and rating. The shubunkin is a single-tail with calico color over blue, 11.8 inches (30 cm) for 50 gallons (190 liters), marked easy.

The rule

What a goldfish needs

A goldfish is a carp, and the bowl tradition does not survive the numbers. The fancy goldfish list 20 to 30 gallons (75 to 114 liters) for one fish and reach 5.9 to 9.8 inches (15 to 25 cm); the single-tails list 50 gallons (190 liters) and reach 11.8 inches (30 cm), which is why they end up in ponds. None of them wants a heater: the single-tails take 39–75°F (4–24°C) and the fancies 59–75°F (15–24°C). They eat a lot and foul water fast, so the filter is oversized and the water change is weekly. And every goldfish in the catalog is marked social, so they are kept in twos or more.

  1. 01

    No bowl

    20 gallons for one fancy, 50 for a single-tail

  2. 02

    No heater

    39–75°F for single-tails, 59–75°F for fancies

  3. 03

    Big filter, weekly changes

    They eat and foul water like the carp they are

  4. 04

    Company

    Every goldfish here is marked social

Single-tails

Single-tails and ponds

The comet is the common goldfish with a long, forked tail, marked easy at 11.8 inches (30 cm) for 50 gallons (190 liters), and the fastest goldfish in the catalog. The crucian carp is the goldfish's wild relative, marked easy and peaceful at 11.8 inches (30 cm) for 119 gallons (450 liters) at 39–75°F (4–24°C), a pond fish that overwinters under ice.

Fancies

The fancy end

The lionhead and the ranchu have no dorsal fin and a hood of head growth, 7.1 inches (18 cm) for 25 gallons (95 liters), marked medium. The pearlscale is round as a golf ball with domed scales, the same size and rating, and it wants the warm end at 64–75°F (18–24°C). The bubble eye carries fluid sacs under its eyes that tear on anything sharp, and the celestial eye has eyes fixed upward; both are 5.9 inches (15 cm) for 20 gallons (75 liters), marked difficult, and neither competes well for food against a faster goldfish.

FAQ

Common questions

How big a tank does a goldfish need?

A fancy goldfish lists 20 to 30 gallons (75 to 114 liters) for the first fish, and add 10 gallons (38 liters) for each one after it. A common goldfish, comet or shubunkin lists 50 gallons (190 liters) and does better in a pond.

Do goldfish need a heater?

No. The single-tails list 39–75°F (4–24°C) and the fancies 59–75°F (15–24°C). A tropical tank at 78°F (26°C) is too warm for them.

Can goldfish live with tropical fish?

Not with most. The white cloud mountain minnow shares their range at 57–72°F (14–22°C); tetras, barbs and livebearers want water 10 degrees warmer.

Why does my goldfish tank get dirty so fast?

Goldfish eat constantly and produce waste like the carp they are. Oversize the filter, feed once a day, and change a third of the water every week.

Which goldfish are hardest to keep?

The bubble eye and the celestial eye are marked difficult: they see poorly, lose food races and injure easily. The pearlscale, ranchu, lionhead, oranda and ryukin are marked medium.

Is a goldfish a good first fish?

The common goldfish is marked beginner, but it needs 50 gallons (190 liters). For a small tank the fantail, marked easy at 20 gallons (75 liters), is the goldfish to start with.

Index

All goldfish

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