Pothos in the tank?

[JBAwrench]

Pothos sap is toxic to humans and animals. Roots growing in the filter chamber away from fish would likely be safe, perhaps, but once the roots or stems are in the tank there is a risk the sap could enter the water if the stem/root is opened. The following [from https://smartgardenguide.com/are-pothos-poisonous/] is just one of several near-identical warnings online. I would not subject my fish to this torture.

Are Pothos poisonous? Yes, Pothos plants are poisonous if ingested and can be irritant to the skin if touched. They are not known to be fatal, but they will cause irritation to your lips and tongue, and they can make you vomit. Make sure to keep the plant away from cats, dogs, and children.​

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The thing that makes Pothos plants poisonous is the insoluble calcium oxalate crystals contained within their leaves and stems. These crystals resemble small glass shards that will physically pierce and cause localized irritation to the skin when touched, or the mouth and digestive tract when chewed or swallowed.​

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In very rare cases, ingestion of part of a Pothos plant can also cause swelling of the upper airway, making it difficult to breathe.​

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All parts of this plant are toxic if ingested, so be very careful and make sure to keep it away from pets and children.​

As well as several other plants

I only knew about the Pathos plant toxicity because it came up some time back and I researched it. Philodendrons are I believe also toxic. No idea about Spider Plants.

I understand the idea behind growing terrestrial (house) plants with their roots in an aquarium (tank or filter), as this should remove nitrates from the aquarium water. I do not have a nitrate problem, so I have never bothered with this, and given the risk I doubt I ever would. If nitrates are occurring solely within the aquarium, by which I mean they are not already present in the tap water, it is easy to keep them very low. As for whether house plants will deal with nitrates in the tap water, I've no idea how effective this might be.

Point is, that without some proven benefit, it is better not to risk the fish.

Rush, is a house plant that I have fully submerged in water and they grow well for about 6 months then begin to die.
Pothos has never harmed any of my fish and I would speculate in nature their are also toxic plants that the fish would come in contact with and know to avoid eating.
I have never heard of anyone confess to pothos killing their fish on any forum.
Their is a youtube video of a lady who was growing algae in her 200 gallon and she added some pothos to the filter and after a month it killed all her algae and took her nitrates from 80ppm to 10ppm so as far as its water filtration properties it is top notch in my book.

 

[Byron]

Pothos has never harmed any of my fish and I would speculate in nature their are also toxic plants that the fish would come in contact with and know to avoid eating.
I have never heard of anyone confess to pothos killing their fish on any forum.

There is no way you can know if this plant has or has not harmed your fish, unless you are a microbiologist and perform a necropsy. We can however assume the risk is present, given the toxicity of the plant. No aquarist should subject fish to such a risk when there is absolutely no need for doing it.

s for fish in nature, this is misleading. Fish have an instinct programmed into their DNA relevant to the local environment. But it goes beyond even this. If this plant in thee aquarium were to become ruptured, the confines of the aquarium make it much deadlier than it would ever be in nature where the relative vast expanse of the water would make it much less of an issue.