The TRUTH about "Goldfish Bowls" Contrary to popular belief, goldfish are NOT suitable for fish bowls. Why? Namely because they require much more than a simple fish bowl can offer. A juvenile goldfish (2 inches) requires, at the very least, five gallons of water. When provided with less space, its growth will be stunted and it will be prone to growth defects. Its lifespan will also be greatly shortened. If the fish is kept in a non-aerated container, select the one with the largest surface area. More oxygen will be absorbed through this area. A bowl with no aeration must be cleaned at least once a week. Even in well-cleaned tanks, goldfish are messy. In a small bowl, a goldfish may grow to three inches and live for a number of months if cared for appropriately. Goldfish in more favorable enviroments, such as ponds, may grow to two feet and live for 15 years or more.