Just thought I would share my experience with the amazing medusa worm.i love weird inverts and picked this guy up a while back .this guy was awsome looked like an alien ,cleaned the rocks like no other ,I found a gem ..had him over 1 year before he decided to nuke my tank ..I woke up in the morning and looked at my tank to find my powder blue tang laying dead on the sand bed. I found this very odd as the night before he was swimming just fine ..I rushed to get him out before he drifted under rockwork ,I threw on The lights to find 4 other fish dead ..all the other tangs I had were breathing very heavy ..then I see a bunch of orange peices all over ..the medusa decided to go into the mp60..he got chopped up.into 3 peices .I quickly got the 3 peices out which were all moving around ..I did a 100 gallon water change ,added a ton of carbon..then did another water change the next morning .all together I lost 6 fish ..after doing some more reading .these guys are highly toxic when stressed .they release something In the water that effects the fishes breathing ..I feel the only reason I had only lost 6 fish was because of my water volume. I have 575 gallons of water .I could only imagine the effect this would have had on a smaller tank .lesson learned for me .I should have did alittle more reading before I had bought him ..