Home· Freshwater Aquarium Blog·How to Use Pothos as a Natural Aquarium Filter

How to Use Pothos as a Natural Aquarium Filter

One of the reasons we love aquarium plants so much is because of their ability to absorb toxic nitrogen compounds (produced by fish waste) from the water, but what if you own fish or aquatic pets that are natural-born plant killers? It’s time to get a pothos plant for your aquarium! While pothos won’t mechanically filter out particles from your tank water, they’re great at reducing nitrate levels (and algae growth) so that you don’t have to do as many water changes to keep your fish happy and healthy. Keep reading to learn more about nature’s miracle gift to fish keepers.

What is Pothos?

Pothos (Epipremnum aureum) is a very popular houseplant that also has the nickname “devil’s ivy” because of its extreme hardiness. It’s very difficult to kill and will survive even in very low light, nearly dark conditions. You often see pothos used not only in aquariums, but also in hydroponic systems and bioactive terrariums. The only caveat is that it is toxic to cats and dogs if ingested, but we have not found any reports of aquarium fish having problems with this plant.

Uaru cichlid

Pothos is a great natural filtration alternative for aquariums with plant-eating fish, like uaru cichlids.

How to Use Pothos in Aquariums

You can easily find pothos on the cheap at your local hardware store or plant nursery. There’s no need to buy a huge plant because pothos grows very quickly, especially in aquariums with heavy bioloads and lots of fish waste. We purchased the smallest size pot for $4 and were able to separate it into six to ten plantlets.

If you’re really on a budget, you can even start with just a single pothos leaf from a friend, and it will readily grow roots in water. However, for faster growth, we prefer to use a little plantlet that already has some established roots. Make sure to thoroughly wash off all the dirt and fertilizer on the roots so that it won’t adversely affect your aquarium’s water chemistry.

pothos plantlet

Separate your pothos into individual plantlets with 2 to 4 leaves each, and thoroughly wash the roots to remove any dirt and fertilizer.

If you keep plant-eating fish, stick the pothos in a hang-on-back filter to keep it out of harm’s way. Set it in an area that is far away from the filter’s motor compartment so that the roots won’t grow into the impeller and clog it up. If your fish won’t attack the pothos, you can put the plant’s roots directly into the tank with its leaves growing out of the water. The aquarium lid should hold the plant in place so that it won’t fall in.

Remove the lid on the hang-on-back filter, and “plant” the pothos in a filter media compartment as far away from the motor as possible. Trim the roots in the future if needed.

Eventually, the pothos will grow into a long vine, which you can guide to climb up the wall or along some shelving. Its long, stringy roots will create a beautiful jungle for your fish to swim in and out of, and you can always trim them if they get too dense. Plus, you can easily cut off a stem or leaf and propagate it into other tanks in the future. With its amazing ability to keep nitrate levels and algae growth down, pothos might be the best filtration you can buy for less than $5!

pothos plant in rectangle glass vase

Pothos plants not only provide excellent biological filtration for your aquarium, but they also grow into a beautiful vine outside of the tank and provide long roots for fish to swim around and hide in.

To find out how often you need to do water changes on your aquarium, download our free infographic that guides you step-by-step through the process.

Recent blog posts