Is it okay to keep a common goldfish in a 1 gallon tank?

Answer 1

Yes, it is okay to keep a small goldfish in a 1 gallon fish tank. But also keep in mind that you should also have a filter in this tiny tank too. Remember that with such a small tank, it is essential to keep the water quality the same from one day to the next. That means keeping the pH and dissolved proteins in check. Yes, it is a goldfish and they are less expensive but they are still fish and would be much happier in a larger aquarium.

Goldfish can breath at the meniscus of the water you are keep it in but they are a type of carp and would be happier on the bottom looking for food. Looking for food in a 1 gallon tank will get pretty old for even the smallest gold fish. Don't be surprised if it stops swimming around looking for food when it learns that the only food is coming from you.

If you got this fish at a fair or someone has given this fish to you and you aren't sure how to keep it happy, it maybe worth it to give it to someone who wants and is ready to take care of a fish.

I say this because a 1 gallon tank is usually used as a "hospital" tank for hatchlings or for a sick fish. It is also used to hatch brine shrimp to feed fish, not to keep fish.

One last thing. If you do decide to keep the goldfish, do not listen to people who want to change the water all the time. You are just shocking the goldfish. With a one gallon tank, replace any evaporated water with distilled water and replace a teacup's worth of water with distilled water, though you can get away with good tap water (depends on where you live). Since it is a small tank, you have to do this everyday though you can get away with missing a day.

All this is on the assumption that you have small gravel on the bottom of this tank. The gravel will be a place that bacteria can grow so it can break down proteins that the goldfish will defecate. Essentially you are creating a septic tank within a tank. The water will turn foggy at first and may take as long as a week to clear but follow what I stated above about water and soon you'll have a stable tank. If it is truly a common goldfish, you will have eventually get it a bigger tank because it will grow out of a 1 gallon tank. It won't be happy but if the water is kept well and you feed it on a regular basis, it will grow.

(Note that this type of answer is my opinion. There is no "rule" on how big or small a tank should be. My opinion is that the smaller the tank, the harder to keep. Bigger the tank, easier to keep.)

Answer 2

No, one goldfish needs a minimum 20 gallons on it's own