The Hazards of Keeping Fish And How to Avoid Them

When thinking of keeping fish, the first thing you think of might not be that it is dangerous. It might be some risks though while thinking of it so I was thinking:

Are fish tanks dangerous? Fish tanks are not dangerous for kids, pets, or adults but there are some risks of having a fish tank. Mainly there’s a risk in the water evaporate making mold grow and the risk of leaks.

There are some more risks to keeping fish that you might not know about. In this article, we will go through every hazard of keeping a fish tank and how to avoid them.

Risks with evaporation

Fish tanks contain water. It’s nothing new. But water evaporates, potentially giving you problems with your health.

The water in a freshwater fish tank has a temperature of about 77 F (25 C). It’s not enough for the water to boil. In fact, it’s far from boiling water.

But the water is escaping the fish tank despite it not boiling. Evaporation is a way for nature to keep the temperature constant. Some molecules are having more energy and escape the water. That’s why we have evaporation.

You will usually see the evaporation as condensation in your fish tank at the glass or the lid.

The evaporation is making the air more humid and that could be a danger for you.

With more humid air, there’s a risk of mold growth.

Your wall will be damp and those conditions are perfect for mold spores (that naturally are in the air) to get a grip and start growing.

The growing mold is weakening your health since the spores are released into the air, possibly giving you respiratory problems. The spores might even be toxic for you.

Allergic reactions are also a possibility when breathing mold spores.

If mold starts growing you have to fix it by contacting a firm helping you get rid of the mold. Do it as soon as you see any mold forming. The earlier you fix it, the less of a hazard it is for you!

The evaporation “problem” is a bigger issue in places where the climate is very dry. With a dry climate, there is more evaporation, potentially making mold grow.

In climates where the air is very humid, like in rain forest, for example, there will be less evaporation. In these climates, it could be a lot harder to keep the temperature of the fish tank though.

That’s because of the less evaporation that occurs, thus making it harder for nature to keep the temperature in balance.

Preventing evaporation

The risks of evaporation could be avoided by having a lid on your fish tank. With a lid, the evaporation is prevented to reach the room and therefore preventing the humidity to get stuck on the wall and letting mold grow.

If you have a lid, be sure to keep an eye out for temperature spikes.

Due to the lack of evaporation disappearing from the fish tank, there is a risk of it rising the temperature in the water making it dangerous for your fish.

If you see the temperature rise, open the lid and let some humidity escape. This will cool down the fish tank.

Also, be sure to do regular and maybe bigger water changes to prevent evaporation.

This will cool down the fish tank and by that preventing evaporation. You could do a water change with slightly colder water added. Make sure the water you add to your fish tank is not too cold though. That could cause the fish tank to fluctuate too much in temperature.

Noice from fish tank

A fish tank will not make a lot of noise. In some instances, this could be an issue.

The small humming noise you get from the pump could be a long-term problem. Also, the splashing of the water that might come from the air pump or a bubbler could be a problem.

The small humming noise could be so small it’s barely noticeable. But the frequency could be pick up by you and be affecting you.

What you might be having problems with are cognitive functions. You might get tired and not feel well.

But since the humming is so low it’s not easy to do the parallel to the tiredness and lowered cognitive functions to the noise of the fish tank.

The solution

Be sure, when buying an air pump that you get a quiet one. Now, most air pumps are marketed as silent. But silent is never completely silent.

Most air pumps have a marking of how much noise they make. Be sure to get the air pump with a lower noise level if you decide between two different air pumps.

You will always get some noise from the air pump so be sure not to put it inside a room where you need quiet or where you are spending all your time.

Such rooms are bedrooms and living rooms. If you put it in any of these rooms, be sure to put the fish tank far away from where you are spending your time the most.

That way you will get the least impact from the humming from the air pump.

Also, be sure to direct the nozzle from the pump so the water doesn’t splash as loudly. You need to break the surface tension to oxygenate the water. But it doesn’t require much to get well-oxygenated water.

The dangerous risk of leakage

One obvious risk is that the fish tank will break or leak. This is what will cost you the most money if anything happens.

A slow leakage will, over time bring water damage to your floor and walls. The worst part with slow leakage is that it’s not always visible or noticeable before it’s too late.

To find a hidden leak, you should monitor your water level inside the water tank. A lot of tanks have lines showing how much you should fill your fish tank with water.

Use these lines to your advantage to find out if the fish tank is dripping water or not.

Another way of finding a hidden leakage is to hear a small dripping noise. Sometimes if the droplets are falling from a higher distance it will make a small splash sound.

That could be noticeable sometimes.

You could have the tank crack and spring a big leak. Then you would have all the water on the floor, causing serious damage to the room or even to the house.

If this happens you should act fast. If the water is spreading it will cause more damage. Do whatever you can to be able to stop the water and to suck all the water up.

It could take weeks or months to dry everything up. Be sure to have insurance covering these types of accidents so you don’t have to pay for everything yourself! It could be expensive!

How to prevent a fish tank leakage

When building your fish tank, be sure the stand you put the fish tank on is strong enough. The weight will be a lot when you put in the water. The best is to get a stand that is made for the specific fish tank you bought. Then you know the weight will be supported.

Be also sure the fish tank is leveled before putting in the water!

If the fish tank is tilting a little bit, the weight will not be evenly distributed and there is a risk of the fish tank cracking.

Be sure the seals are good before putting in the water. An old seal is a common cause of leakage in used fish tanks. The seal could be brand new, but the fish tank has been without water for a long period.

During that period the silicone will dry up and shrink a little bit. When the silicone shrinks the water has a change of sipping in behind and out of the fish tank, down on your floor.

Also be sure that where you put your fish tank no things are risking falling onto your fish tank, cracking it. Such things are cabinets and coat hangers for example.

If an accident happens, you want to be sure there is not a double accident.

Also, be sure not to let anyone or yourself play wildly around the fish tank. If you play with sticks or kick around with a ball you run the risk of hitting the fish tank, causing a crack, and have an accident.

The risks of you getting sick

It’s not very common, but there is a risk of your getting sick while handling fish.

You could catch fish tuberculosis while handling the water in your fish tank. It’s caused by the Mycobacteria and gives fish tuberculosis.

But in us humans the fish tuberculosis is not affecting our lungs. It’s affecting our lymphatic system giving us abscess at our hands and/or arms that doesn’t want to go away.

It’s not dangerous for us since you could get antibiotics and be treated within some weeks. You could heal spontaneously.

The Mycobacteria is not infecting you, as long as it doesn’t get the opportunity to get into your body via a small wound or a crack on your hands.

While inside the body the bacteria are going to the lymphatic system and infecting you.

Since it’s so uncommon to get infected, a lot of doctors don’t even know about fish tuberculosis. The Mycobacteria takes a long time to culture and doesn’t show up on common bacterial culture.

Another risk is the risk of allergies while handling fish. Mostly it’s allergic reactions to the conditioner you put in the tap water when doing a water change.

It’s very uncommon to be allergic to any other thing while handling a fish tank.

Prevent getting fish tuberculosis

Fish tuberculosis is only able to get to you via wounds or cracks on your hands.

To prevent getting wounds and cracks, be sure to moisturize your hands regularly to make the skin soft and less prone to crack.

Also, wash your hand before and after handling your fish tank. That is every time you do a water change.

Wash your hands before doing the water change to be sure you are not infecting your fish and was it after for you to be sure you are not getting infected by your fish.

Wash your hands in warm water. That will remove and prevent the Mycobacteria from infecting you.

Hygiene is everything when it comes to preventing infections. It’s better to wash your hands one time too much than one time too little.

Tell your doctor you have fish tanks and that there is such a thing called fish tuberculosis if you have abscesses on your arms and hands.

In some places in the world, the doctor has to report fish tuberculosis to monitor the cases. By letting the doctor know it could be fish tuberculosis, he or she could do the right type of bacteria culture to find it and confirm it’s fish tuberculosis.

Safety for kids

Fish is a very safe pet for kids to keep. For a lot of kids, their first pet is a fish.

The fish will not attack you and it’s easy to take care of. There are some risks with the equipment though.

Firstly the conditioner, medicine, staring bacteria, or any other liquid you need could get to the kid which might drink it and that’s bad.

These liquids could be toxic, especially for small children!

If your kid gets any of these liquids inside them, you should call 911 or the emergency number you have where you live and tell the person what happened.

Another risk for kids is the scissors you might have to trim the plants in your fish tank. The scissors are usually very sharp and anyone (not only kids) could be cut pretty bad by these scissors.

If you or the kid is cut, try to stop the flow of blood by pressing on the wound. If you bleed a lot or the bleeding is not stopping. Call the emergency number to get help!

If there’s a flake gone from the glass of the fish tank due to hitting the fish tank, there’s a risk a kid will cut themselves on that flake.

If this happens, do the same procedure as when getting cut by a scissor.

Maybe the biggest risk for a kid is that they play around the fish tank and happens to hit the fish tank and break it.

The kid might get glass shards from the tank on them is very dangerous for them.

Prevent kids from getting hurt

To be sure the liquids and sharp things are not available for the kids.

Wither put it high up where the kid can’t reach, or you put it in a cabinet which you can lock or the kid can’t open.

Never have anything that children can hurt themselves on easily available to them. A lot of stands for the fish tank comes with doors and shelves to put all the stuff you need.

It’s uncommon for them to have a lock, I would suggest you add a lock yourself if you want to have your liquids and sharp things in these cabinets and having kids.

To prevent a kid from hitting the fish tank by accident you should never let your kids play around the fish tank. The area around the fish tank should be an area where you could sit and enjoy the fish.

Be careful yourself around the fish tank and be a good role model for your kids. If the kids are taught how to behave around the fish tank, there should be no big risks of having kids and a fish tank.

Safety for other pets

There could be risks of having fish together with other animals around your house. The classic is when the cat is fishing from the fish tank.

While this is a risk for both the fish and the cat it’s mainly a risk for the fish. The cat could fall into the tank, but it will quickly get out and dry up.

It’s a stress for the cat though so it’s not for the cat itself. But it’s more stressful for the fish to have a cat inside the fish tank.

Any animal with fangs could also scratch the window of the fish tank. Small scratches are not usually a problem, the problem is if it gets a lot of scratches and if they get deep into the glass.

Then the scratches could get into cracks, releasing all the water onto the floor.

If a pet is inside the fish tank with its paw or something else, there is a risk of it catching infections from the fish tank. There is a lot of bacteria all around in the fish tank making it a risk for the pet.

Prevent risks with other pets

To prevent the risks of fish and other animals interacting with each other, it’s best to keep them separated. It’s easiest done with a lid on the fish tank preventing the cat, dog, or other animals from getting into the fish tank.

Some pets can remove the lid though. Then you could clamp the lid.

If going for the clamping method, be sure you still have it a little bit lose to get good circulation underneath. If it’s too tight you will have a problem with the temperature in the fish tank.

Another way to separate your other pets is to do it physically.

Having a fish tank in another room or at a place where the other pets don’t have access is also a solution.

This could be hard though depending on how big you live. It might be physically impossible to cut the access of your pet into another room. Also, you might want to enjoy your pets all at once.

It’s better to teach your pet how to interact with the fish.

If this succeeds you might get a pet wanting to protect the fish and who knows? Your other pet might also like to sit in front of the fish tank and enjoy the fish.

Risks with feng shui

If you are into feng shui, there is a risk of putting the fish tank inside your bedroom.

According to feng shui, the water element resembles calmness. But since you need movement at the surface of the water inside a fish tank you are also moving the calmness destroying it.

In the bedroom you need calmness!

This will disturb your energy and make you less stable.

This is easy to prevent though. Just don’t put your fish tank in your bedroom! If you live small and are into feng shui, you should either have a size that suits where you could put it or don’t have a fish tank at all.


While keeping fish is very safe, there are some risks to take into consideration.

The main risk is the fish tank to leak, potentially destroying your house or apartment. Or the risk of the evaporation causing mold that could be hazardous for both you and your pets.

The hazards against us humans are also the risk of cutting ourselves or having allergic reactions. Also, the risk of drinking the liquids needed for a water change. But, if you are careful there should be very small risks.

Even getting infections from the fish tanks are very rare. It’s still a risk to consider though. That’s because it’s quite common to have small wounds at your hands, especially if you are living in a dry environment. It’s through these cuts the bacteria could get a grip and infect you.

The infections are not very serious but it’s better to avoid them if you can. No one wants to be sick from such a simple thing.

The other risk is when you have another pet, the pet could stress themselves or the fish. Stress for a long time is harmful, no matter what kind of animal.

So, be safe and careful with yourself, your kids and your pets and everyone and everything will be fine!

Related questions

Can a fish tank explode? A fish tank can explode if there is a crack bursting it open. But it will take a lot for it to be able to break, as long as you have the fish tank leveled and the correct amount of water in it.

Is it bad to sleep next to a fish tank? It’s not harmful to sleep next to a fish tank. However, the noise from the pump and the splashing of the water could affect your sleep and make you have a worse night sleep.


I have been a fish keeper a big part of my life. During the years I have gathered and searched a lot of information about fish keeping and here, on the website, is where I share that information to help you with your fish keeping. I want to provide the information that I didn't get when I had a question about my fish tank.

Recent Posts