Probably. I had to break down my tank due to texas trash poly infestation. They are very toxic to humans also, I would start a plan to erraticate asap.
I would try injecting the lower stem(s) with vinegar or kalk paste and see if they shrink up. If they do, you can eradicate them this way. Assure youre running fresh carbon in case any toxins would be released but should not from a syringe