For years, there has been a stereotype that a bowl (and a Betta fish in it) is an ideal solution for people who want to have a fish, but do not want to have a big aquarium. More than once, I have come across a statement like: “My Betta lives in a sphere and is doing great”. Often, the further conversation with such a person showed that the fish do not swim much, often “hang” motionless or hide wherever they can. The fact that some Betta fish are able to survive in such harsh conditions proves only the endurance of these fish. However, in such conditions, they will never show us their full potential and beauty. In fact, the bowl is only suitable for growing plants or for storing candy. Keeping any fish in it is torturing them. In many countries, the sale of such tanks is prohibited by law. Why? I explain it in this material.

Very small tank volume

The sphere is a very small reservoir in which it is extremely difficult to maintain biological balance. Theoretically, to eliminate these negative factors, such a tank would have to have a minimum of 30 liters, but those available on the market usually do not even have 5 liters. Small volumes of water do not have buffering capacity. This results in a much faster pollution of the water with metabolic products and food debris than in larger aquariums, which causes poisoning, bacterial infections, etc. This in turn causes the death of fish, or at least shortens their life.

Little space to live for a fish

There is very little space for swimming in such a tank, especially in a straight line. The fish in the bowl feels just like us if we lived our whole life in a room with a very, very small area and round walls where we cannot throw the garbage, we have a sleeping corner and a kitchen and a bucket instead of a toilet.

No place for a good bacteria

The bowl has a minimal bottom surface, in which beneficial bacteria cannot settle, which transform fish waste into ingredients available to plants. It is also not possible to plant a large number of plants that absorb harmful substances from the water and provide the opportunity to hide for a fish. Every animal, even a fish, hides when it feels unwell. In such a sphere, fish is stressed all the time because there are no hiding places. Constant stress causes a decrease in immunity, which means that the fish become ill more easily and live shorter.

Difficult gas exchange

Due to its shape, proper gas exchange does not take place in the bowl . In other words, the fish is choking and the water deteriorates. One might say that in the case of Betta fish, it does not matter, because he breathes the atmospheric air. Unfortunately, a very poor exchange of CO2 into O2 in the water leads to the accumulation of harmful compounds, and this results in disease and even death of the fish.

Inability to install a filter, heater

In small – up to 30 liters – sphere tanks (most often bought by customers), it is very difficult to install water treatment equipment, i.e. a filter. The seller says it’s unnecessary, but are you drinking your piss? It is also difficult to find a place for the heater, and if you manage to do it at the expense of a small space. It is also difficult to mount the cover that all labyrinth fish need to prevent them from catching a cold.

“Washing Machine Effect”

The bowl has no angles, so the fish swims in a circle, which will quickly lead to problems with the labyrinth (“washing machine effect”). Such a fish, transferred to a normal aquarium, will not regain health and will struggle to the end.

Permanent stress

Fish have a special organ to perceive water vibrations, which is the side line. The slightest movement causes its vibrations to bounce off the walls of the aquarium and all other objects, allowing the fish to orientate themselves in their surroundings. In the sphere, the waves of vibration very quickly reflect off the walls and circulate between the arc of glass and the body of the fish. As a consequence, the fish still pick up their own echo, which causes constant stress, which is why some fish hardly ever move in such tanks. In addition, by placing an artificial plant, we are doing the fish a disservice, because if it is already swimming, it can easily be injured by hard elements.

Loss of sight

The bowl distorts the view (lens effect). When we look through the wall of the sphere, both we and the fish see a distorted image. By looking at the rounded world from inside the bowl and the refracted light, the fish loses its sight.

Problematic cleaning

Cleaning the bowl is usually done by taking everything out and scrubbing it under running water. This is the worst possible solution. In this way, we provide the fish with a drastic change in water parameters, which negatively affects its health. In addition, we get rid of useful bacteria and break the biological balance.

Often, instead of living plants that take part in water purification, artificial ones are chosen for the bowl. They look unnatural, do not improve the conditions in the aquarium, and the fish can easily get cut by hard and sharp plastic.

So why do they sell small sphere tanks in pet stores?

Because they are more expensive than a classic aquarium. So the seller can count on a profit. Informing the customer about the need to buy a filter and a heater may scare him away from buying a popular Betta fish, so the stereotype of a Betta as a fish without requirements that survives even in a glass is still great. Maybe he will survive, but what will life be like?

So instead of a bowl, let’s decide on a small aquarium (e.g. 25-30 l) with full equipment. It takes up more or less the same space as such a sphere tank, but it has a much larger volume than it and does not have its negative features. I can assure you that in a classic aquarium the fish will feel much better, their disease incidence will decrease and they will simply look better.