The truth about putting a goldfish in a fish bowl
I'm going to start this off by saying that I certainly DO NOT recommend anyone, ever, to put a goldfish in a bowl. It is a very unhealthy environment for a goldfish to live in, even if it can survive in it. Even being able to survive in it is a stretch for most of them. Surviving doesn't necessarily mean healthy. Most people just don't know why this is the case. After all there are so many products that are designed to get you to buy just that, a goldfish bowl. On top of that how many people have kept goldfish in a bowl as a child? If you did you may recall that it died very quickly or parents you may recall constantly going to the pet store to find a goldfish that looks just like the one that just died, and trying to do it quickly before your child comes home. I've seen it many, many times.
Firstly, a goldfish is going to outgrow a bowl. Very easily. I'm sure that somewhere along the way you've hear "A fish will only grow to the size of the space you put it in", this is simply not the case. A fish is going to go to the size it's going to grow to regardless of what you put it in. If you put a newborn baby in a shirt for a toddler, the baby isn't going to stop growing just because it eventually got big enough for the shirt to fit right? Same goes for fish. If there is no longer any space for it the fish may, attack other fish or fish them out of the tank, become very sick, jump out themselves to find room, or just die. A goldfish can get up or a foot long or bigger! Now, that isn't going to happen in a few weeks or months, goldfish don't grow quickly but one day it will get big. As you can see from the picture below, it's no joke how big a goldfish can get.
Also, Goldfish are extremely messy fish. They produce a lot of waste, which produces a lot of ammonia, which takes up the oxygen in the bowl, so your fish can suffocate in a matter of hours or days! Since that can happen pretty quickly, you would have to change the water constantly to keep oxygen in the bowl and just to keep it clean. I've know people to clean their goldfish bowl 3 to 4 times a week! That's way too much cleaning for any fish, not to mention extremely stressful. Not just the fact that the fish is being moved but also the fish isn't going to be use to the new water! That may seem like an odd statement, but all fish need water that has a good bacteria set up in it. If the water is constantly being changed there is no way for the water to become fully established for a fish to be healthy.Not to mention that all that ammonia can make that bowl smell pretty bad.
There is also a very high chance that the Goldfish can become sick very easily. Ick (white spots appearing on the body), Fin and tail rot (fungus), septicemia (a blood infection, showing as long red lines in the fish's tail and fins), or a bacterial infection resulting from the stagnant water. It's hard to find medication for these diseases because most medications are designed to require moving water and at least 10 gallons of water
Besides a Goldfish will most likely jump out of a bowl anyway. In the end a goldfish bowl is way more trouble than it's worth.
Always have at least a 10 gallon tank for small goldfish. Remember the more fish you have in the tank the more cleaning you have to do, the quicker the fish will out grow the tank, and there will be a much higher chance of problems from poor water quality. I would also recommend a filter designed for a tank higher than what you have. For example, a filter that is designed for a 15 gallon tank for a 10 gallon tank. This will provide extra filtration power to help keep the tank cleaner and a gravel vacuum to help keep down the huge mess goldfish can produce, and make sure to test and do partial water changes regularly to promote clean water for your fish!
Gravel vacuums are great for all tanks not just for goldfish! They make cleaning so much easier