Does your tank need a filter if you only have plants inside and no livestock? This goes for all sorts of nano tanks, jars and other types of aquariums where the main focus is the aquascaping and not necessarily the fish living there.
Today, we’re discussing whether or not aquarium plants need a filter.
The answer is no. Aquarium plants don’t need a filter to survive and thrive. I have several tanks without any type of filter installed and the plants are thriving. So unlike fish, plants don’t need an internal or external filter to survive and thrive.
Believe it or not, some plants don’t even need additional light sources to do well. I wrote about the best low light plants for aquariums in the past – make sure to check that out for a good starting point for low maintenance plants that don’t really need much…
But back to plants in the aquarium and filters!
As long as you don’t have any livestock in the aquarium, you don’t need any sort of filter for your plants to do well.
Even more, with a heavily planted tank and minimal livestock living there, you can also easily have a thriving aquarium without a filter.
You see, plants are basically the filter in the water. They are fed by all the debris in your tank and instead release oxygen that will keep the water clean.
But ideally, unless you are a very experienced aquarist, it’s best to only keep plants in an aquarium without a filter, and no livestock.
This is very common for many hobbyists out there who build self-sustaining water ecosystems, usually known as jarrariums. Due to their small size, these have no room for installing a filter and do absolutely fine.
My personal experience with aquarium plants & no filters
My oldest jarrariums are 5 years old and completely self-sustaining. They have plants only (no fish, shrimp or snails) and have been going on without me doing even a partial water change for years.
So you definitely don’t need a filter for aquarium plants to do well.
Even if you add livestock – depending on how much you have and how heavily the tank is planted – you might do really well without a filter.
I have a 2.6 gallon jar that is heavily planted and populated by a huge dynasty of red cherry shrimp and snails, without any sort of filtration and with minimal external light.
This one has been going for over two years without problems, although I do a partial water change every month or two.
Because one thing that plants can’t filter is the actual residue that your aquarium inhabitants leave behind. While for a well balanced tank, this would have no effect over the water quality and only look bad, it doesn’t hurt to remove all that goop anyway.
I am a big fan of creating self-sustaining ecosystems and I have to admit that it’s pretty difficult to achieve that balance when livestock is present.
But I do have a 30 gallon (120 liters) aquarium that is heavily planted and has livestock inside and absolutely no filters. The secret is to keep a minimum of fish that produce minimum amounts of debris.
As a result, I only have 12 Microrasbora Galaxy as fish and an impossible to count number of shrimp (probably around a hundred).
With minimal feeding and no water filter, the aquarium is doing great and the plants are thriving without added CO2. It’s a perfectly balanced ecosystem that I am extremely proud of.
And I only perform a water change in this huge tank ever 2-3 months. It’s been running like this for 2.5 years!
But if you’re just starting and don’t want to add a filter to your aquarium, do start with plants only. Livestock will complicate things a lot.
Why don’t plants in an aquarium need a water filter?
The water filter has a very specific role in an aquarium (we’ve talked about this in the past). To put it short, its main role is that of removing debris like decaying food and fish poop from the water, as well as removing toxins like ammonia and nitrates and also to oxygenate water.
But – except for the capacity of actually removing the debris from the water – this is exactly what plants to in an aquarium.
That organic matter, the extra nitrates and even the ammonia are basically plant food. So they eat that all up, filtering the water. They do it at a slower pace than a filter and this is why most aquariums need one: because they have too many fish and too little plant life.
But if you only have plants in your tank or a lot of plants and few fish, then you don’t really need a filter. Anybody who tells you otherwise has no idea what they’re talking about.
Conclusion
So, if you’re considering starting up a jarrarium, a nano tank without a filter or any sort of water ecosystem with plants only, know that it is completely safe to do so without adding a filter.
Once your system gets established and the plant life is flourishing – and if it’s large enough – you can even consider adding some sort of livestock. But know that once you do add livestock, the balance can quickly change.
And now for a lot of amazing examples of water ecosystems built without any sort of filtration, make sure to check out the Jarrariums reddit. Be warned, though: if you don’t know what jarrariums are, chances are you’ll get a new addiction!