If i'm posting in the wrong section, im so sorry.
I got a betta fish before I learned that pothos roots and peace lily roots can make them sick. I still want to get them for nitrate control though, so my question is, would putting them in my HOB filter still hurt my betta? or is it only if ingested?
Sooooo, the internet is full of people that get one piece of information, and then use their 'common sense' to draw any number of odd conclusions from this that may or may not be true. This would be one great example.
There are a LOT of plants both aquatic and terrestrial that we keep in our homes that actually somewhat toxic if ingested by humans and/or animals. This does not mean they actually are toxic to be around.
In the case of a peace lily and a betta, the betta is not going to eat the roots. They are not herbivores. It is perfectly safe to have a peace lilly with the roots submerged and the plant in the air in a betta tank. If you tried to grow the peace lily completely underwater with all the leaves submerged, it would die and rot, and that nutrient imbalance from the rotting plant matter could certainly kill a betta, as it would any other fish. This has nothing to do with the toxicity of the plant and everything to do with a plant rotting in an aquarium.
Sooo tl;dr, go ahead and put the peace lilly roots either in the filter or the tank itself, your betta will be fine. Just make sure you wash it well before adding it to get rid of any fertilizer used to grow it.
