i came home today and find my anemone stuck in my filter. How do I prevent this from happening again? It's upsetting because my anemone was already hosting my clown.
You can't stop it from detaching itself and floating around the tank. The most you can do is keep the parameters stable and not change the lights or flow or it'll keep moving. The last two are the main reason way anemones will either move or detach their foot and float around the tank. I know Sebae anemones are notorious for floating around the tank also.