Pothos is a popular houseplant that thrives in aquariums.
But a few years ago, the plant gained notoriety for “destroying” a woman’s aquarium. Soon after the woman introduced pothos, the prolific plant seemingly removed the aquarium’s decorative brush algae.
Naturally, some hobbyists are concerned that pothos plants could harm their aquariums.
This article will discuss those concerns, explaining the pros and cons of pothos. Plus, keep reading to learn how to install and maintain pothos so that you can maximize the benefits of this decorative plant.
Video: Pothos DESTROYED my aquarium!
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What is a Pothos Plant?
Pothos is a tropical vine plant with waxy, heart-shaped leaves. In the wild, this trailing plant can grow up to 40ft long. Indoors, pothos can reach up to 30ft in length.
Pothos grows fast, requires minimal care, and is difficult to kill – all traits that make it a popular houseplant. So if you’re shopping for pothos, you might see it referred to as devil’s ivy, ivy arum, hunter’s robe, taro vine, or its scientific name: Epipremnum aureum.
The plant’s aerial roots help pothos adapt, grow, and thrive in many environments. These roots also make it very easy to propagate pothos plants.
Although it is a terrestrial plant, hardy pothos plants have gained popularity in home aquariums because they provide many decorative and practical benefits. Pothos can also improve hydroponic systems and bioactive terrariums.
Neon, Jade, and Golden Pothos are best suited for semi-aquatic growth as they are the most tolerant to shallow and poor light conditions.
Other varieties of pothos include Cebu blue pothos, Hawaiian pothos, Manjula pothos, marble queen pothos, and pearl and jade pothos.
Pothos roots absorb nitrous compounds from the water. This water purification is especially useful in fish tanks, as fish waste contains high nitrate levels.
Unlike some aquatic plants that fall prey to nibbling fish, pothos roots are hardy (and unappealing) enough to resist such nibbles.
Offering both practical and aesthetic benefits, the pothos plant sounds too good to be true. But is it? Read on to find out.
Is It Safe to Put Pothos Plants in an Aquarium?
Maybe you’ve heard that pothos plants are poisonous. But that’s not exactly true.
The leaves and stems of pothos plants contain insoluble calcium oxalate crystals. If ingested, these crystals will cause discomfort. They essentially act as tiny shards that cut the mouth and digestive tract.
But pothos plants are rarely deadly and do not contain poison.
However, they are still toxic to humans and pets. So keep the plant away from curious kids, cats, and dogs.
What about fish and other aquarium critters?
Yes. These crystals can hurt the mucus membrane of a fish. But keep reading.
The insoluble crystals occur within the leaves and stems of the pothos. But as the next section will outline, these toxic bits should not touch the water’s surface.
Instead, the leaves should hang above the water. The roots should be the only part accessible to fish. (There is little evidence to suggest that pothos roots are toxic or poisonous to fish.)
Plus, pothos plants are hardy – roots included. Nibbles from goldfish, betta fish, and other popular home aquarium inhabitants won’t gain much purchase on the roots. Shrimp and community fish will be more inclined to nibble the algae that can grow on the pothos roots.
The hardiness of its roots makes pothos an excellent addition to hermit crab cages. In addition, pothos is not known to be poisonous to turtles or other reptiles.
There is one caveat to this safety evaluation. If you install the pothos incorrectly (i.e. submerging it underwater), it will eventually die. Left to decay in the aquarium, the dead plant might create an excess of nitrogenous waste that could harm or kill your fish.
The last thing to consider is whether or not a pothos will kill the other plants growing in your aquarium.
Technically, pothos itself is not deadly to other plants. But it excels at soaking up nitrates, so a pothos could rob other plants of necessary nutrients. And without those nutrients, the other plants will die.
Long story short, if you want to cultivate decorative algae in your aquarium, avoid adding pothos to the equation.
How to Attach Pothos to an Aquarium
Although a popular addition to fish tanks and aquariums, pothos is not an aquatic plant. It is tolerant of poor light conditions. But if you submerge the pothos foliage underwater, it will eventually turn yellow and die.
Want to spruce up your aquarium? Follow these steps for successful pothos installation.
1.) Establish the Right Growing Conditions
Pothos is an easy-growing plant, but you still need to establish ideal conditions to plant one in your aquarium.
- Water Temperature: Pothos are tropical plants. They will do best in water temperatures between 75 to 80°F.
- Humidity: Pothos thrive in humidity levels above 70%.
- Light: Avoid planting pothos in direct sunlight. Moderate light will help the plant’s leaves maintain vibrant colors.
- Nutrients: Pothos plants love nitrates. Goldfish are prolific nitrate producers. But if your water doesn’t have the necessary nutrient levels, you can add liquid fertilizer to the water.
2.) Prepare a Clipping
Pothos propagates quickly. It also excels at nutrient uptake. These two traits mean you don’t need to install a ton of pothos in your aquarium. Instead, start with a small clipping.
If you already have a pothos plant trailing around your house, you’re in luck!
Select a pothos leaf and locate the node (a small bump where the leaf meets the larger stem). You’ll want to cut a few inches below this node. Use sharp scissors to take the cutting at a 45-degree angle.
Once you have your cuttings, place them in a container filled with water. This water should be free from chlorine.
Place that container in a location that gets moderate light. You will need to change the water in the container to maintain the oxygen levels necessary for the plant’s growth.
Keep the clippings in a separate container until roots have formed. This root formation takes up to 20 days. Shorter cuttings will form roots more quickly than longer cuttings.
You can buy small pothos plants with established roots designed for aquatic use. If you purchase one of these plants, wash the roots before adding the plant to the water. You want to remove any dirt and fertilizer that could cause a chemical imbalance in your aquarium.
3.) Install the Plant
You can transfer your pothos cuttings from container to aquarium as soon as roots have formed. More established pothos will be easier to manipulate than smaller pothos plants, but either way, the roots will continue to grow in the aquarium.
When selecting a location for the pothos, place the plant away from the filter so that the roots don’t clog this system.
Hang an aquaponic or aquarium plant holder so that the basket sits in the water. Place the pothos inside the basket, keeping the stems and leaves above the water’s surface. Only the roots should be submerged.
As the pothos grows, you can guide the trailing leaves and stems to decorate the aquarium’s exterior.
4.) Monitor & Maintain Growth
After the roots have been established, it takes about two months for the plant to reach full maturity. Pothos can grow between 12 to 18 inches per month in ideal growing conditions.
Trim the pothos when necessary to avoid overgrowth. Overgrowth could clog filtration systems and lead to nutrient depletion for other plants.
Once you’ve added a pothos to your aquarium, you might need to make small adjustments in your overall aquarium maintenance regime.
Pothos roots provide natural filtration, meaning you might not have to change the aquarium’s water as frequently.
Whether or not you will need to fertilize the pothos depends on your aquarium’s ecosystem. The fish waste provides high levels of nitrate, acting as a natural fertilizer.
In most cases, pothos plants reduce algae growth. However, if your aquarium sits in direct sunlight, algae might build up on the pothos’ roots. To prevent algae growth, move your aquarium to a less sunny location.
Direct sunlight might also cause the leaves of the pothos to turn yellow. If moving the aquarium into a shadier spot doesn’t correct this issue, the water’s nitrate levels are likely low.
To remedy this issue, you can add liquid fertilizer to the water. Or introduce goldfish. These fish produce waste containing high levels of nitrate.
Stunted leaf and root growth also indicate low nitrate levels or poor light conditions.
Pros of Planting Pothos
Pothos plants do more than add decorative flair to your aquarium.
- Water Filtration: Fish waste and leftover fish food naturally contain nitrates which, in large quantities, can harm aquatic ecosystems – even killing fish. Pothos plants purify water by absorbing nitrates and ammonia through their roots.
In less than a week (four to five days), pothos can lower nitrate levels by 20-40 ppm. So if you’re looking to neutralize nitrates in your aquarium, pothos is the way to go.
Pothos plants will not remove physical particles as a mechanical filter would, but they still improve water quality for your fish. Plus, it means you have to change the water less frequently.
- Reduced Algae Growth: Decreased nitrate levels make it more difficult for algae to grow, keeping the aquarium’s water clean and clear.
- Improved Air Quality: Pothos plants benefit humans as well as fish by removing pollutants and some odors from the air. Even when their roots are underwater, above the water leaves absorb pollutants such as carbon monoxide, benzene, xylene, toluene, and formaldehyde.
- Water Aeration: It might sound counterintuitive, but fish need some oxygen to survive. Pothos roots helpfully absorb carbon dioxide and release oxygen into the water.
- Additional Coverage: The root system of a pothos provides shade and coverage for small fish. This coverage allows weaker fish to hide from aggressive tank mates.
The added shade also helps mimic the natural environment, providing fish a place to rest, breed, and lay eggs.
- Substrate Stabilization: Depending on how expansive the root system is, a pothos can help keep your tank’s substrate in place. When the pothos roots grow into the substrate, they minimize disturbance from filter uptake or rowdy fins.
Many aquatic plants offer similar benefits. But pothos plants outperform their competitors largely thanks to their fish resistance. Since pothos foliage grows above water, fish can’t eat or otherwise damage the plant.
The Pitfalls of Pothos Plants
Ecosystems require balance to survive. The danger of adding pothos to an artificial ecosystem like an aquarium is that this plant grows quickly, making imbalance more possible.
- Nutrient Deficiency: Pothos plants excel at absorbing nutrients from the aquarium. This nutrient uptake can rob other aquarium plants of necessary nitrates. So if you’re hoping to grow algae in your aquarium, avoid putting pothos plants in the water.
- Strong Root System: The strength of pothos roots means they are well adapted to resisting fish nibbles. The downside is that these robust roots can take over the aquarium without proper maintenance and trimming.
In some cases, the roots can clog and damage mechanical filtration systems.
- Toxicity: The roots of pothos plants are not poisonous to fish and other aquarium critters. However, the leaves and stems of this plant contain insoluble calcium oxalate crystals. If ingested, these crystals cause irritation and discomfort.
Fortunately, these pitfalls are easy to prevent with proper maintenance and attention.