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Can Goldfish Thrive in a Bowl? The Surprising Answer

Brooke Billingsley

June 23, 2021

We’ve all been there; the aisle in the pet store that’s lined with dozens of fishbowls of different shapes and sizes. We’ve also all run into someone who insists that keeping goldfish in a fishbowl is animal cruelty and abuse. They insist that you should have a gallon for every inch of fish in the bowl, and that a large tank is the kindest thing for your goldfish. This can be pretty confusing when you consider that some of the longest-lived goldfish on record were kept in bowls. Anecdotally, tons of people claim to have kept a goldfish alive in a fishbowl for 15 years or more. So, what gives?

Here’s the thing:

Keeping a goldfish in a bowl can be cruel, but keeping a goldfish in a poorly maintained large tank is just as cruel. Goldfish can thrive in a fishbowl but there’s very specific care that goes into keeping a goldfish healthy in a fishbowl.

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What Makes a Healthy Goldfish Bowl?

Filtration

Ryukin Goldfish_Ek Ing, Shutterstock
Image Credit: Ek Ing, Shutterstock

Goldfish create a ton of waste, or a heavy bioload, in their environment. They’re messy fish, and some people even believe that goldfish can’t be kept with other fish because of this waste load. Goldfish can be kept with other fish, but the filtration of the environment is extremely important, whether it’s one goldfish or 20.

Aquarium filters don’t just remove small and large waste particles from the water, but they also serve as the perfect location for the colonization of beneficial bacteria. These good bacteria consume things like ammonia and nitrite. Beneficial bacteria prefer environments with moving water, making filters a hotspot for these good guys.

Aeration

Ryukin Goldfish
Image Credit: Ammit Jack, Shutterstock

You may have heard before that goldfish can breathe air, and that is true to an extent. Goldfish have a specialized organ, called a labyrinth organ, that performs similarly to a lung, allowing them to breathe room air. They also have gills, which allow them to breathe oxygen from the water. But just because a goldfish can breathe room air doesn’t mean they should have to. Poorly oxygenated water will lead to distress in your goldfish and eventually, death.

The labyrinth organ is not made to replace the need for gills, it simply serves as a survival mechanism for goldfish. Providing aerated water for your goldfish will introduce oxygen into the water that your goldfish will be able to use for oxygenation via the gills. Aeration also means you have water movement, which improves your beneficial bacteria colonization and provides a better environment for your goldfish, which tend to prefer moving water.

Plants

goldfish plant_gunungkawi, Shutterstock
Image Credit: gunungkawi, Shutterstock

It seems common that people with goldfish in bowls seem to keep fake plants. Maybe it’s a concern about space in the bowl or available lighting, or maybe it’s just the mistaken belief that plants are nothing more than a decorative addition to fishbowls. It’s a common misconception that live plants aren’t necessary in a goldfish bowl.

The addition of live plants to a fishbowl improves the oxygen available in the water, and plants consume some waste products, like nitrate, to help them grow. Live plants are natural filtration systems and while they don’t replace a full filtration system for your goldfish, they are a beneficial addition. Many aquatic and semi-aquatic plants are easy to grow and will thrive with regular natural or room lighting.

Water Quality

Goldfish _dien_Shutterstock
Image Credit: dien, Shutterstock

Filtration and aeration are only two pieces of the puzzle when it comes to providing excellent water quality for your goldfish. Dangerous waste products, like ammonia, will rapidly build up in a goldfish’s environment. They build up most quickly in small environments, like a fishbowl. A filtration system and live plants will help pull ammonia, nitrite, and nitrates from the water, while aeration provides oxygen and water movement needed by both goldfish and plants. It’s important to cycle your fishbowl before adding goldfish. A fish-in cycle will be much more difficult in a small environment like a fishbowl.

To maintain water quality in a fishbowl, routine water changes are necessary. How frequently this should occur will depend on how many goldfish are present and the size of the environment they’re living in. If you’re intending to keep goldfish in a fishbowl, it’s safe to assume you’ll need to perform water changes weekly at a minimum. Treating new water added to the bowl will remove toxins like chlorine and it will replace some of the waste products with clean water.

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What Should I Purchase to Make a Healthy Goldfish Bowl?

  • Filtration: Depending on the size and shape of fishbowl you purchase, you have multiple options for a filter. Hang-on back and canister filters tend the be the most efficient, but they are not usually a good fit for a fishbowl under 10 gallons or so. Smaller bowls can usually accommodate an internal filter or an undergravel filter.
  • Aeration: A proper filter will aerate your goldfish’s bowl, but it may not be enough to provide a well-oxygenated environment for your goldfish. Air stones and bubblers are both great additions that don’t take up much space in a fishbowl. Many goldfish enjoy playing in the bubbles and can often be seen chasing them or swimming up and down in the current.
  • Plants: If you intend to get a grow light, then you have a huge number of plants to choose from. For regular room lighting, stick to plants that can survive low-light environments. Java fern, Java moss, Aponogeton, and Anubias are all good options in low lighting. Floating plants, like dwarf water lettuce, red root floaters, and Amazon frogbit, are great picks for reducing nitrate levels. Remember to check the full size of the plants you’re interested in to ensure they’re appropriate for the size of fishbowl you have.
  • Water Quality: Invest in a high-quality water test kit and use it frequently, especially while cycling your fishbowl before you add a goldfish. You should also invest in equipment to perform water changes, even if it’s a basic gravel vac and bucket. Keep products on hand that reduce chlorine, ammonia, and nitrites, as well as products that can alter pH levels if needed.

How Big Should My Goldfish’s Bowl Be?

goldfish bowl_New Africa_Shutterstock
Image Credit: New Africa, Shutterstock

Unfortunately, there’s not really a one size fits all answer here. If you’ve heard before that goldfish won’t outgrow their environment, you should know that that’s pretty much true. Goldfish produce growth inhibiting hormones which build up in the water. The smaller the environment, the more dense the hormones are. These hormones basically tell the goldfish’s body to stop growing, stunting growth. Even with this stunted growth, some goldfish may grow to a size that is uncomfortable in a small space and require a larger environment.

If you are starting with a small goldfish, like a feeder fish, then starting with a small fishbowl less than 5 gallons should work fine. Some goldfish live happily in 3-5 gallon bowls their entire lives, but ideally, an adult goldfish should be kept in a bowl that is at least 10 gallons. This will provide leeway with water changes when life gets busy and ensure the water quality is maintained. The smaller the bowl, the more frequently you’ll need to perform water changes. Small fishbowls under 5 gallons can even require daily water changes.

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Conclusion

When it comes to keeping goldfish in fishbowls, you’ll definitely run into people who believe keeping goldfish in fishbowls is cruel and deadly. Oftentimes, these people have had their own negative experiences with keeping a goldfish in a bowl. You’ll find that people who have had these negative experiences didn’t understand the needs associated with keeping a goldfish in a bowl. They may have not realized the necessity of filtration, water changes, or aeration. Many people don’t even understand the need for cycling before the addition of fish, and many people who do know about water cycling aren’t sure how to do it. Keeping a goldfish in a fishbowl is a big commitment and you may find it much simpler to keep a large bowl or tank to reduce water changes and make care of the environment easier.

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Featured Image Credit: LUIS PADILLA-Fotografia, Shutterstock

Brooke Billingsley

Brooke Billingsley spent nine years as a veterinary assistant before becoming a human nurse in 2013. She resides in Arkansas with her boyfriend of five years. She loves all animals and currently shares a home with three dogs, two cats, five fish, and two snails. She has a soft spot for special needs animals and has a three-legged senior dog and an internet famous cat with acromegaly and cerebellar hypoplasia. Fish keeping has become a hobby of Brooke’s and she is continually learning how to give her aquarium pets the best life possible. Brooke enjoys plants and gardening and keeps a vegetable garden during the summer months. She stays active with yoga and obtained her 200-hour yoga teacher certification in 2020. She hosts a podcast focusing on folklore and myth and loves spending her free time researching and writing. Brooke believes that every day is an opportunity for learning and growth and she spends time daily working toward new skills and knowledge.