Can You Keep Guppies in a Glass Fish Bowl?

You’ve probably seen this stereotypical setup before. I’m talking about goldfish in a glass bowl. This image is ubiquitous, and there are legitimate reasons why people opt for a glass bowl. But before you rush to buy the perfect glass bowl for your guppies, you might want to reconsider this option.

In this article, I’m going to discuss the advantages, disadvantages, dangers, and possible alternatives to the glass bowl, so that you can make the best decision for your future fish tank. So, without further ado, let’s get started!

Is A Glass Bowl a Good Idea?

I understand that for a newbie fish-keeper, space and equipment costs might be a concern. A glass bowl is simple, compact, cheap, and looks very nice as a decorative piece on your desk or side table. You might be thinking, and justifiably so, “I don’t need a lot of space. I just want to keep one or two fish.”

That’s true, but there are a few extra things to keep in mind when setting up the perfect home for your pet fish. You’ll be surprised to learn that keeping fish in a bowl is a pretty bad idea. Actually, without trying to sound dramatic, a glass bowl is probably the worst possible way to keep fish, apart from keeping them in a plastic bag.

The sad truth is that fish can’t thrive in a glass bowl. And the reasons why go far beyond space. This applies to goldfish, guppies, and any other fish species. So, let’s look a little deeper into this. Why is a glass bowl a bad idea, and what are some other affordable, space-efficient options?

Why Can’t Fish Thrive in A Glass Bowl?

I advise against glass bowls for growing and keeping guppies, or any fish for that matter. This small, constricted space might be okay for keeping a few snails or shrimp. But even in the case of tiny fish species, a glass bowl is a death sentence. Your best bet would be to convert your glass bowl to an aquascape because plants are the only living thing that could survive in this habitat.

But why exactly is the humble glass bowl so horrible? Well, there are three main reasons. First, there’s the obvious issue of space. Then there’s filtration and dilution. Lastly but equally important, there’s the problem of water parameters. Because a glass bowl is so small, there’s little you can do to equip it properly. As a result, these issues are difficult to avoid.

Guppies need at least 2 gallons of water each, but more is better. An average glass bowl holds around 1-3 gallons of water, which is barely enough for one fish. Guppies require plenty of space to move around, but water volume is also important for filtration. Guppies produce waste constantly. If your fish are crammed inside a small space, there won’t be enough water to dilute the harmful waste products.

Without proper toxin dilution and water filtering, the water pH drops quickly and harmful ammonia builds up. This brings me to the next factor— unstable water parameters. The more water in your tank, the easier it is to control water parameters without sudden changes.

A low water volume means abrupt fluctuations in temperature, pH, water hardness, and toxin build-up. Such unstable conditions are hard to monitor. These sudden changes in water parameters can also shock your fish, causing multiple health problems.

Can You Install a Filter On a Glass Bowl?

A water filter is mandatory for any fish tank. Using one is the best way to ensure the water stays fresh longer. A filter diminishes the risk of ammonia poisoning, and it keeps the water pH stable. So, can you install a filter on your guppy bowl?

In theory, you could, but your options are going to be limited. Internal filters are a bad idea. Most of them are too spacious or too powerful for a small bowl. Hang-on back filters are a poor match due to their size and shape. It would be pretty difficult to fit a HOB filter along a rounded bowl edge.

You’re left with two choices. Either a small external canister filter or a sponge filter. Both of them look awkward if you ask me. If you want to save more space, the sponge filter would be the best choice. However, any type of filter on a fishbowl is an eyesore.

Keeping Guppies in A Glass Bowl

I don’t recommend keeping Guppies in a bowl for an extended amount of time. However, there are some ways to make it work for a short while. With careful monitoring and frequent maintenance, your guppies could be relatively healthy. But you’d have to be very careful about the setup and maintenance.

I suggest keeping only one guppy in a glass bowl, maybe two at most. Swimming space will be a problem nonetheless, but reducing the number of fish per gallon helps to keep the water fresh. Feeding your fish excessively is never a good idea, but you’ll have to be especially careful when using a fishbowl.

Any food leftovers will sink to the bottom of the bowl and decompose, leading to further water pollution. Also, make sure you don’t have a male and female pair because guppies are prolific breeders. You’ll have to buy 20 additional fish bowls before you know it.

The water must be well filtered and oxygenated. Definitely install a suitable filter for your guppy bowl. Add a thick organic substrate and lots of live plants to help with the water purification.

The plants and the beneficial bacteria in the substrate will keep ammonia and nitrites to a minimum. Last but not least, add a bubble stone aerator to keep the water well oxygenated.

The Best Glass Bowl Alternative

Here comes the good news! If you’re interested in keeping guppies but don’t have enough space for a traditional fish tank, there are better alternatives. A glass bowl has the main advantage of being space-efficient. But this setup is inconvenient in basically every other way.

Enter the nano tank. This tank is compact, minimalist, yet versatile. Compared to traditional tanks, nano tanks come in smaller sizes. Most are spacious enough to keep at least 3-5 guppies. They usually come pre-equipped with a water filter. While they might be pricier than glass bowls, they’re a good investment for casual fish keepers.

Nano tanks are the perfect compromise between fish bowls and traditional tanks. They’re small enough to fit on your desk. They’re modern and easy to upgrade. You can switch and install any type of filter, heater, or aerator. They also come in a variety of shapes and height or width ratios. You’ll surely find something to suit your taste.


Glass bowls look cool. There’s no denying that. But it’s best if you keep them for aquascaping. Trust me, your guppies will thank you later. The sad truth is that glass bowls are not suitable for keeping fish, for a variety of reasons. Whether it’s space, filtration, or water quality, there’s nothing that a specialized fish tank can’t do better.

Luckily, there are some nice alternatives for small tank enthusiasts. You don’t have to stick to the bulky, old-fashioned tanks if you don’t want to. Nano tanks offer the same aesthetic experience and space-saving perks, without being a health hazard for your fish.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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