A filter keeps the aquarium running and is necessary for most of the settings. It mimics the ecological environment that fishes are habitual to. So, how long can a fish live without a filter?
Fish can survive in an artificial environment without a filter for about 3 days to a maximum of a week. The number of days is mostly dependent on varying factors such as the number of fish, measures you are going to take to ensure filtration, the resources you have, and alternatives.
Now, you might also think that goldfish do really well in a fishbowl without a filter, as well as few show-fish. Or is it just an iconic memory from a movie that shouldn’t be practiced? Do you really need a filter for your aquarium? Let’s get to the root of it all.
How Do Fish Live In Natural Environment Without Filters?
This is the very first question that would come to anyone’s mind if one has to debate on the need for a filter for their aquarium.
Isn’t clean water enough for them? Don’t they just need water to ‘breathe’? Actually, no. This would be simplifying their problem.
Fish don’t just need water but the oxygen that they get from water. Still waters hardly ever have fish in it.
You can find fish in rivers or even oceans too where water circulates. But shallow ponds can also breed fish better than still waters, why? Isn’t it interesting? We’ll get there too in a while.
Role Of The Process ‘Cycle’ In Artificial Setting
Now, let’s try to understand what we are exactly trying to mimic in an artificial setting (fish tanks and aquariums) through the process called cycle.
- Fish produce ammonia and if that gets accumulated in a fish tank, it will get lethal for them to survive. It can affect their life expectancy and health.
- To counter this problem, live bacteria are added to the aquarium. These live bacteria attach themselves to the sponge and other filtering material – your standard filter. Once they start to live and breed, they consume this ammonia and create nitrite.
- Then, a second set of bacteria makes their home in the filter and consumes nitrite to produce nitrate. This whole process is called a cycle.
Since ammonia and nitrite are highly toxic for fish, it is essential to ensure there is a bacteria growth in your aquarium before you put them in it.
A filter pumps air and circulates water inside of the aquarium. When the filter stopped working for any reason, the first hit is always caused to the bacteria living in the aquarium – they will start dying off.
Still, water doesn’t have enough circulation to produce oxygen. Hence, your fish will be swimming up to get some ‘gasp’ of air. Those fish who cannot do that will suffer more.
How Do Fish Survive In Shallow Ponds?
Rivers, oceans, and freshwater lakes all have natural filtration available to them via live bacteria, water circulation, etc. However, if there are many fishes in a shallow pond, they tend to live to a quite much extent.
It is because the movement of fish in shallow water creates enough air and oxygen to circulate in the shallow pond. Also, since the space between water and air isn’t so far, thick or deep, they can get oxygen much more easily.
However, it is not an ideal environment to live in and they do not tend to survive for a longer period because of other factors such as predators, water evaporation, no frequent change of water, etc.
Do Fish Like Goldfish And Betta Fish Do Good In Fishbowls With No Filter?
The short and simple answer to it is – they don’t. Any new fish-keeping hobbyist might be in such an illusion.
Doing this will either make your resolve stronger in maintaining the fish better or leave fish-keeping as a hobby altogether. Maintaining fish is not an easy or cheap job.
As we have cleared it before, clear water is not enough for fish to survive. People generally tend to keep fishbowl with the idea of saving space and money. Why buy filters when you can fill it up with clean water?
Without a filter, you will have to regularly filter water, changing it, and refilling it – maybe every day or at least every 2 days. Otherwise, you will observe your fish dying. In such cases, it is better to have a fish or two in a bowl, nothing more than.
Moreover, it is never a great idea to fill the fishbowl close to its brim. In every aquarium, it is always beneficial to fill the bowl or a tank till half or little over half if there is no filter there. In case we have a filter, then you can fill it close to the brim.
We all remember iconic stills in movies where a hero or heroine will be observing a fish in a bowl, swimming, all clueless – while our protagonist muses over it. But as a fish keeping practice, this is tedious work and even harmful.
After all, they never show what happened to the fish in the bowl as the movie ends. Did it ever have a happily ever after? These are the questions we need to ask.
How To Save Your Fish During A Power Outage?
The downside of having a filter would be keeping it vulnerable to a power outage. If your area has power outage issues, this is going to create havoc for the fish.
Your fish can survive this if you are ready to save them on time. Let’s first tell you the simplest and basic solution to it.
Getting a generator or inverter will help your filter, heater, and everything running smoothly. Inverters are generally cost-friendly for a longer term than generators as it needs fuel and the former needs batteries.
If you do not want to keep your fish vulnerable to the power outage, especially when you cannot be around to change the water and do the needful – it is good to invest in the inverter. If you want to go for generators, it can work out nicely as well.
Now, let’s get to the part where you cannot always afford to have an inverter or generator. There is nothing to feel bad about it but you have to be proactive about saving them.
You have a time window of 24 hours maximum to make the necessary arrangements!
This is how you can do it.
Buy an additional water tank where your fish can swim. Fill half the tank with the existing water and exactly half of it, nothing more.
Balance the population. The idea is to make fish swim in the water and induce circulation through their movement. If it gets overcrowded, shift half of them in another tank.
If you have larger fish, it is always a good idea to buy a kid’s pool (bathtub) and shift them there.
If you have plants in the tank, do not add them. Aquatic plants also need oxygen they get from water. This way, they will not be competing for oxygen. You can keep them stored in a plastic bag filled with water.
Do not feed the fish. They can live up to 2 weeks without food. The reason not to give food to them is that it will dirty the water. Filter always cleans food particles along with water circulation and pumping air. Leftover food will also deplete oxygen present in water.
Do not mindlessly add live bacteria to the new tank. The live bacteria may be able to eat ammonia, but it will not be able to properly form a second set of bacteria that eats nitrate. This will not produce a cycle that we are intending to create. Instead, it can get toxic for your fish.
The best thing to do would be to check the ammonia level in the water, pH as well as water temperature. It should be according to the needs of the fish. Just when the ammonia level rises in water, you would need to change it.
In case you are doing this for bigger fish and shifting them to a kid’s pool, make sure that you cover it with a net so that they do not jump out of water.
If these things get really tedious for you, you can ask your friends for help and shift your aquarium to your friend’s place who has an inverter or generator available to them.
Make sure that when you refill the water again in the tank, do not put the fish and wait for it to create a cycle. It is better to add ammonia in the water and wait for it to create a cycle, and then add fish back to the tank.
These steps should help you save your fish in time and give them a happily ever after (unlike those innocent and clueless fish prisoned in a fishbowl).
Not all fishes have eyelids to indicate they are sleeping, except for sharks. They sleep with their eyes open (a technique that would have been so useful to us humans in boring situations). So, can fish sleep with the lights on?

Many of us dream about having an aquarium in our homes but are worried that it is too much work. I have also looked into getting an aquarium and did some research as to how much work it really is and which aquarium will suit me best.
Now that you have purchased a 10-gallon tank, you need to think about its inhabitants, and how you will make that corner of your house interesting, which was previously occupied by your grandmother’s coat stand.
This species of bottom-dwelling fish is one of the most popular ones. They remain tiny and do not normally grow longer than a few inches. They are highly compatible with other species, but most importantly, they are omnivores.
These can be another great addition since they only grow up to 2 inches. They are called by several other names like Oto cats, algae scrapers and dwarf suckermouths.
As their name suggests, Siamese algae eaters love algae no matter what the type is, therefore any algae that might be toxifying your tank may not be found the next morning.
The Amano shrimp is adaptable to various tank environments and are one of the most productive algae eaters in the family of shrimps.
Loaches have a unique personality and love to live in groups with other species of fish, so there is passion and it is seen in their movements around the tank.
The Pleco fish lives between 20-30 years and may grow as long as 2 feet. It not only constantly feeds but is nocturnal too.
They are cuter than Cory Cats and flit around and scour the bottom of the tank all day.
Their small appearance is interesting and their behavior is quite intriguing too, but some of their species can grow to a certain length that may not be suitable for a 10-gallon tank.
Your fish will give you indicators that something isn’t right in their tank even if everything else seems to be fine.

Some fishkeepers love to see their fish thriving in harmony, then there are some who love to see their turning into a Roman colosseum! If you don’t fall into the latter category, you might be worried about your fish fighting or eating each other off. Good thing that we have the answer to that!


In the wild, betta fishes are found in shallow waters like floodplains, rice paddies, and canals. So one might think that using artificial lights in their aquarium may not be too good for them. But, are betta fish sensitive to light? And if they are, what are the effects?
