Are Round Bowl Fish Tanks Bad For Fish? You Should Know

Ryan Chilton
4 min readJan 7, 2021


Photo by Sadiq Nafee on Unsplash

Fishkeeping as a hobby has been around for 2000 years. Before that fish were raised in ponds for consumption. Today, fishkeeping is a widely renowned hobby. Makes you wonder what is the best way to raise your fish friends.

Yes, they are bad for fish. But, a small amount of space is perfect for guppies, dwarf cories, and tetras. The main concern is underserving your fish and water volume plays a big role in this.

What Do You Need For A Fish Bowl?

  • Beneficial Bacteria
  • Good Aeration
  • Room Temp. Water
  • Dependable Heater

Beneficial Bacteria

When you hear bacteria it’s normal to think of the bad kind of bacteria but all bacteria are not bad. Without good bacteria, we wouldn’t have a life here on earth. It’s essential to have good bacteria in order to help keep your fish and its ecosystem alive.

Here is what beneficial bacteria looks like under a microscope.

As your fish eats its meals and then excretes, the debris will settle at the bottom of the tank. Over time this can be very harmful to your fish. Having good plants can break this excrement up then release oxygen back with the particles. As this happens you have excess chemicals these can be brought down more with good bacteria and water changes.

Using both effective water changes and good bacteria can eliminate these harmful chemicals making your fish happy and healthy.

Good Aeration

Aeration is the process of allowing particles, water, and nutrients to move freely with roots to strengthen plants. With good aeration, the soil will not be too compact to not allow proper airflow. This can lead to plants not providing sufficient living conditions.

Good aeration is essential to allow fish to beath in good, clean, quality oxygen. Yes, fish breathe in oxygen just like you and me. knowing that means that it’s essential for them to have good aeration.

With a round bowl it’s a good idea to have plants for aeration but also would be nice to have a waterfall filter or spray bar. Space is essential so having too many means wouldn’t do any good for the fish.

Room Temperature Water

Much freshwater fish enjoy water temperatures between 60 degrees and 75 degrees. Heaters are essential to maintaining water temperature so having a good reliable on really can help extend the lively hood of your fish. Knowing this it's a good idea to have a thermometer present to ensure that the water doesn't go too high.

When you are adding water to your fishbowl it’s important to note that the source will determine the overall outcome. Tap water or spring water is good to add to your fishbowl. However, making sure to add a conditioner to the water will help with chemicals.

What Makes A Fish Bowl Bad?

What makes a fishbowl bad is precisely the opposite of what makes them good. Without proper aeration, your fish will suffer as well as beneficial bacteria. Without proper water parameters in place, the fish will become stressed.

This is a bad example of having a round fishbowl. Unfortunately betta fish are not good for keeping in fishbowls because they should have at least 5 gallons per betta fish to move around, interact, and for excretions. Betta fish will also fight in close courters so it’s best to give them enough space to roam.

Do Round Bowl Fish Tanks Stress Out Fish?

Being confined in a small bowl would stress out your fish most indefinitely. The only exception is small fish such as guppies.

Being a big fish in a small pond isn’t a bad deal. But, being a big fish in a small fishbowl would stress me out.

When your fish is stressed many different things can happen.

  • When your fish is stressed they will not eat. Loss of appetite can lead to poor cognition resulting in the slow movement. Think of yourself in their shoes. They aren’t too different from us with their emotions. When you are stressed you are most likely not in the mood to eat. Why should it be any different for your fish?
  • As your fish becomes more stressed they can have an increased chance of acquiring a disease. Unfortunately, they can die but given that they give you signs that means you have time to make them better.
  • Often when there isn’t enough oxygen in the bowl they will gasp at the surface. This is a sign that the quality of water isn’t sufficient enough for them. Adding plants, a good oxygen source, and aeration rocks can better the water quality.

Many different things can happen when they are stressed out. Here is a YouTube video showing how one way they can act when stressed out about adding warm water.

stressed out about adding warm water

Personally, I am claustrophobic so I can imagine how they may feel about the space issue. It's interesting how much it can affect them in good ways and bad ways. Of course, this comes with the hobby of fishkeeping which is why it is fascinating.


Ultimately underserving your fish can lead to serious outcomes but serving them properly will result in a happy life. When you make the perfect aquatic environment your bowl/tank is happy. When you keep in mind Beneficial Bacteria, Good Aeration, Room Temp. Water, Dependable Heater then you will have the best outcome.

Some fish can live up to 50 years! Which is pretty insane but also very cool.

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Ryan Chilton

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