I've had planarian worms for about two months. I've cut back feedings heavily, wiped them off my glass daily, did daily water changes & gravel vacs, used Cupermine (Copper), used Prazipro, and never yielded any results. Last week I ordered Fendenbazole which is a dog dewormer but they have "Fish Bendazole" I purchased from Amazon. I did my last dosage yesterday and ever since the first dose I haven't seen ONE worm so now 4 days after initial dose and 1 day since last dose and haven't seen any worms. I've done a lot of research on how to get rid of these harmless pests so I am writing this to save everybody their time and money! If you ever get these guys, buy this medication. Let sit 2 days after last dose then do nice water change/gravel vac because once the worms die off they will cause your nitrites to potentially spike (mine didn't spike so I guess it varies) & add your carbon if that's what you use. Just wanted to share my experience so if anyone ever comes across this hope I can help save you time and money 