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Are Small Fish Tanks Cruel? Vet-Approved Guide to Ethical Fishkeeping

Brooke Billingsley

By Brooke Billingsley

muliple sized fish tanks

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Dr. Luqman Javed

DVM (Veterinarian)

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The correct fish tank size seems to be the argument that nobody can ever come to an agreement on. Some people say that any fish can live in any size tank with the right commitment to care and maintenance, while others have specific rules, like a gallon for every inch of fish in the tank. What’s the right answer, though? Nobody wants to intentionally be cruel to their fish, but are some people unintentionally being cruel by keeping small aquariums? Not necessarily, but there really isn’t a straight answer to this question.

aquarium plant divider

Are Small Fish Tanks Cruel?

Whether or not your fish is being kept in a cruel environment is dependent on multiple factors. The type of fish, size of fish, number of animals in the tank, filtration provided, water quality, and more can all make the difference between cruelty and a healthy environment for your fish.

It’s important that your fish is provided with adequate space to swim and move. This varies, depending on the size and type of fish. Some fish like having lots of space to move around, while others prefer to be kept in close quarters because it makes them feel safe.

Water quality is also extremely important. In fact, poor water quality is a top cause of illness in pet fish. Many people are unaware of how to properly maintain high water quality in their aquarium, primarily due to not knowing about the nitrogen cycle.

Overstocking or providing too little filtration for the size of your tank and the number of fish in it can lead to major reductions in water quality. As a general rule, the more fish you have in your tank and the smaller the tank is, the more maintenance it’s going to need. This also varies based on the bioload of the fish you have. A goldfish or Plecostomus is going to create a far heavier bioload than a handful of ember tetras.

Above all, it is important to remember that fish tanks do not have a moral compass and therefore, they cannot inherently be cruel or magnanimous. Furthermore, “small” isn’t a defined size, and therefore, an aquarium which is small in the opinion of one hobbyist might be considered large by another.

Ultimately, all fish species have their individual requirements which hobbyists should be aware of prior to adopting them. Intentionally housing a fish in less than ideal conditions could definitely be considered cruel.

Free-swimming aquarium fish in a fish tank
Image Credit: huang yi fei, Shutterstock

How Can I Tell if My Fish Is Thriving?

If you’re unsure if you’ve created an appropriate and healthy setup for your fish, start by checking out what their natural needs are and make sure your tank mimics that environment. Issues like tropical fish being kept in unheated tanks or a lack of live plants are usually relatively easy and quick issues to fix. Some issues, like inappropriate tankmates, may be more difficult to solve.

A good indication of the health status of your fish is to watch for signs of stress. A stressed fish is more prone to illness. Healthy fish are usually content with their environment. Lethargy, inappetence, bottom sitting, fin clamping, dullness or color changes, glass surfing, bullying, unusual hiding, poor growth, a bent spine, fin damage, and illnesses are all indications that your fish is stressed about something in their environment. In a tank with poor water quality or an inappropriate setup, your fish will almost certainly become stressed.

Are Fishbowls Considered Cruel?

While you likely have an image of a goldfish living a perfectly happy life in a fishbowl, this topic is becoming more controversial. Believe it or not, fish are sensitive animals and require stimulation just like other pets. While keeping fish in a bowl was once acceptable, more and more places are banning this practice, such as Monza, Italy.

Many hobbyists believe that keeping a fish in a bowl is inhumane. Without filters to clean and move the water, little space to move, and a low surface-to-air ratio, it is always best to avoid this. In fact, we highly recommend against it if you truly want to give your fish a good life.

And if you don’t want to dedicate the time and money to keeping a proper aquarium, fishkeeping might not be the hobby for you.

clean fish
Credit: satit_srihin, Shutterstock

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In Conclusion

No matter what, you need to maintain a commitment to providing your fish with the best care possible. Oftentimes, if your fish is in a small tank or your tank is overstocked, then there’s a good chance that you’ll need to provide stronger filtration and more frequent tank cleaning and maintenance than if your fish was in a larger tank.

Always thoroughly research the needs of a fish before bringing it home. Some fish should be kept in groups, which may mean more space, while other fish can get very large and need lots of space. Some fish are happiest with lots of hiding places and won’t take advantage of having lots of open space in their tank.

A small fish tank isn’t automatically cruel, but the environment can become cruel if you aren’t dedicated to providing your fish with the appropriate care. This can apply even if your tank is large, though!

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Featured Image Credit: panpilai paipa, Shutterstock

Brooke Billingsley

Authored by

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...Read more

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