So, can a goldfish survive in a bowl?
The short answer is yes – for a while. Many people equate the fact that a goldfish can live for some period of time in a bowl with their ability to live in a bowl in general. The most common “comet” goldfish are generally cheap (under $0.25US) and sold while very small – usually less than 1 inch long and pet stores often have bowls in the vicinity of the gold fish. All of this makes it reasonable to believe that they can be kept in a bowl.
No, they can’t.
There are two major problems with keeping goldfish in a bowl
- There is no filtration in bowls, allowing ammonia and nitrite to build up – both of which are quite poisonous to fish
- A bowl is not large enough for a goldfish to grow to it’s intended adult size of 6 to 8 inches.
The first problem can be mitigated with frequent water changes and light feeding. The second problem can’t be solved in a bowl.
So, what can I expect if I keep a goldfish in a bowl?
In the best case, goldfish kept in a bowl that is regularly cleaned will live for several years, and will die from no apparent cause. In the worst case, the fish will be weakened from ammonia and nitrite poisoning and will succumb to a bacterial and/or parasitic infection, usually visible as dropsy (where the scales stick out).
What is the best habitat for goldfish?
The best habitat is a large pond.
A more reasonable habitat for most goldfish keepers would be a tank holding over 20 gallons with a filter, for a single goldfish. Add 10 gallons for each additional goldfish.
Don’t make the problem worse!
Too often, well intentioned “goldfish-in-a-bowl” keepers will see their goldfish displaying what is actually symptoms of infection or ammonia poisoning and interpret those symptoms as “loneliness”. They will go out and purchase a second fish to go into the polluted bowl. The combined fish now produce ammonia even faster.
Now that you know a single goldfish should not live in a bowl, you will certainly know not to add additional fish to a bowl.
Here are some videos that will show the size that goldfish will grow to if given the proper environment: