Hi I am presently have a 210 gallon tank that I have used for octopi and will be again when the opurtunity presents itself. Right now I have an angel and wrasse in it that I want to medicate with praziquantel. It's used to kill parasites like worms and flukes. I've used it effectively in my main system which has a shark and other fish. Does anyone have any experience with medications and there effect on octopus. Of course I would do a large water change once fish are treated and are put in my main system. I will also check water parameters before I obtain another octopus . Thanks for your help.