Fancy Goldfish: Tank Size, Tank Mates and Setup
A round-bodied coldwater fish that grows large and produces a lot of waste. Plan on 20 gallons for the first and about 10 more for each extra fish.
- Minimum tank
- 20 gallons
- Temperature
- 60–74°F
- Group size
- One or more
- Adult size
- 6 inAll levels of the tank
- Usually needs no heater at normal room temperature.
- Needs strong filtration and large weekly water changes.
- Not a bowl fish, and not a good match for tropical community fish.
Carassius auratus. Figures are commonly published care ranges; see how it works.
How many fancy goldfish per tank size
The most you could keep if fancy goldfish were the only species. Open a size in the builder to add tank mates.
| Tank | Fancy goldfish, kept alone | |
|---|---|---|
| 5 gallon | Too small (needs 20+ gal) | |
| 10 gallon | Too small (needs 20+ gal) | |
| 20 gallon | Up to 1 | Plan this tank |
| 29 gallon | Up to 2 | Plan this tank |
| 40 gallon | Up to 2 | Plan this tank |
| 55 gallon | Up to 3 | Plan this tank |
| 75 gallon | Up to 5 | Plan this tank |
What you need for a fancy goldfish in a 20-gallon tank
A starting setup: 1 fancy goldfish in the smallest standard tank that suits them.
20-gallon tank
- These fit a 20-gallon tank and get along. Aim for about 67°F.
Equipment, sized for this tank
No heater needed: these do well at about 67°F and your room is 68°F.
Starter supplies
Paid links. As an Amazon Associate, TankStarter earns from qualifying purchases. Sizes are estimates from published care guidelines, not hands-on testing.
Fancy goldfish tank mates
These share a temperature range and temperament with fancy goldfish, with no warnings from our checks.
Use caution with: betta, neon tetra, cardinal tetra, ember tetra, rummy-nose tetra, black skirt tetra, guppy, endler's livebearer, platy, molly, swordtail, zebra danio, white cloud minnow, harlequin rasbora, chili rasbora, cherry barb, tiger barb, corydoras catfish, pygmy corydoras, bristlenose pleco, otocinclus, kuhli loach, dwarf gourami, honey gourami, pearl gourami, angelfish, german blue ram, cherry shrimp, amano shrimp. Add them in the builder to see why.
Plan a tank around fancy goldfish
Add tank mates, check the stocking level and get the equipment sized for your tank.
Open the tank builderFancy goldfish questions
What size tank does a fancy goldfish need?
At least 20 gallons. A larger tank is more stable and gives you more choice of tank mates.
How many fancy goldfish can I keep in a 20-gallon tank?
Up to about 1 if they are the only species in the tank. Fewer if you add other fish.
Do fancy goldfish need a heater?
Usually not. Fancy goldfish does well at 60–74°F, which is normal room temperature in most homes. Use a thermometer to confirm.
What fish can live with fancy goldfish?
Good matches include nerite snails, mystery snails. They share a temperature range and temperament with fancy goldfish.