I had a bunch of these hitchhiking green paly's in my tank several months ago, they came from the local fish store. I removed them all after visiting the local fish store (where they hitchhiked from) and seeing the owners face, which looked like she had been hit repeatedly with a baseball bat on the right side of her face. When I asked her what happened she said that she had touched the palys and (not thinking) rubbed her eye. These things are deadly imo. I don't know how many times I have gotten a gross mouthful of SW when starting the siphon for a water change. It makes me wonder if it would have killed me, had I gotten some of the paly "juice" in my throat.