Technically, you cannot over-filter a fish tank. Still, there are many mistakes you can make with your fish tank filter.
From choosing the wrong size to introducing too much current to your aquarium, filtration mistakes are common among newbie fish keepers.
Fortunately, too much filtration is not something you have to worry about. In fact, most people make the mistake of under-filtration.
What Happens If You Over-Filter a Fish Tank?
As we mentioned above, you cannot over-filter a fish tank, but if you introduce the wrong filtration systems to your tank, you could create too much current.
Filters that are too powerful for your tank could stress out your fish or keep aquarium plants from taking root. In the worst-case scenario, weaker fish could be sucked into your filter.
There are also rare instances of excessive filtration causing filter feeders, like shrimp, to starve because they cannot find enough debris to eat.
Can I Use 2 Filters in a Fish Tank?
Yes – in fact, many fish keepers recommend having 2 filters in your tank, so you have a backup if one fails.
To work properly, fish tank filters need to be cycled or embedded with your tank’s nitrite-eating bacteria, so some fish keepers purchase used filters or keep 2, so they always have a cycled filter ready to go.
Also, keeping 1 small filter on either side of the tank may provide more even filtration, and it’s definitely better than having a filter that is too big or too powerful for your tank.
Can You Have Too Big a Filter in a Fish Tank?
Yes. Although some aquarium hobbyists tell new fish keepers to purchase a filter that is rated for a larger aquarium, you can err and purchase a filter that is too big.
If your filter is too big, it could create too much current in your fish tank, negatively affecting your fish and aquatic plants. As we mentioned before, it could also suck up smaller fish.
Some fish, like cichlids, need bigger types of filters, but others, like betta fish, prefer slow-moving water and may prefer a smaller filter.
How Do I Know If My Fish Tank Filter Is Too Strong?
Seeing is believing. If your fish tank filter is too strong, you will see your fish struggling to swim. You may even be able to see the current or observe that your tank constantly appears unsettled.
If your filter is always full of debris, no matter how clean your tank is, this may be another sign that your filter is too strong.
You should always reduce the flow if you suspect your fish tank filter is too strong because too much current can have a negative impact on your fish’s health.
For instance, your fish can become tired, stop eating or get stressed. Sometimes, a strong filter can even damage delicate fins.
Should I Switch Off My Filter When Feeding Fish?
It’s up to you!
If your filter has the correct flow rate, it should not matter too much whether or not the filter is on, and if the current is too strong for your fish to eat, you’re better off reducing the flow rate, anyways.
Sometimes, fish get lazy and will hide behind the filter waiting for old food to come to them, so if this is the case, it may be worth turning off your filter.
If you are feeding fish at different levels, turning off the filter might make it easier for you, too.
At the end of the day, your filter should not be interrupting feeding time. If it is, your filter may be too big or your flow rate may be too strong.
What’s the Best Way to Filter My Tank?
The best way to filter your tank is to choose a top-rated fish tank filter that fits both your tank and the type of fish you have.
If you want to increase your fish tank filtration, consider installing an appropriately sized filter on either side of the tank, or better yet, introduce some filter fish feeders to your tank.
Shrimp are great to filter feeders, easy to care for, and get along with practically any type of fish (including bettas).
Introducing a bottom feeder, like a pleco, can also help you keep your tank clean without introducing too strong a current.
Live aquarium plants can help keep your tank clean and oxygenated, as well.
Do I Have to Have a Filter for My Fish Tank?
Yes! According to PetMD, you must have a filter for your fish tank to ensure your fish can breathe.
The filter will also help you keep your tank clean, so you can stick to regular maintenance and partial water changes, as opposed to larger changes that put your fish on edge.
Overall, choosing the right filter is what’s best for you and your fishy friends.
Don’t Worry About Over Filtering
If you’re setting up your fish tank, don’t worry about over-filtering. Instead, choose 1 to 2 filters that are the correct size for your tank and the type of fish you plan to get.
Do choose a filter that can handle your needs but do not choose a filter that is more than a couple of sizes bigger than your tank (because you can choose a filter that is too big)!
We recommend choosing a filter with an adjustable flow rate, so you can slow down the current if it ever seems too fast for your fish.
We also love filter feeders (like shrimp), bottom feeders (like plecos), and live aquarium plants to help you keep your tank clean.
While there is no such thing as over-filtering, choosing the right filter is important for your tank, and a filter that is too big or too small could seriously harm smaller, weaker, or more delicate fish.
In summary, don’t worry about over-filtering but do choose an appropriately sized filter and be knowledgeable about your fish’s needs.
If you’re wondering what kind of water parameters your fishy friends need, please check out our species-specific care sheets.