saw this swimming around in my tank one day (never seen it before) thought it was weird but it was big so i took this photo the next day i woke up and saw it in my clown fish's gill, half of its head was in it while the bottom half was out. i went through a few of my books and heard to get rid of hitch hikers to dip it in fresh water so i did that for half an hour nothing. the clown fish was not looking well and i was panicking so i scooped out the clown fish with the net, got tweezers and tried crushing the thing, (it went crunch and was hard) but it still wouldn't move from the gills. so i decided to risk it and pull it out. it was holding onto its gills I'm pretty sure as when i pulled it out i heard a few rips. put the clown fish back, was swimming but a little slow and could tell shocked anyway here's the photo's of it once i took it out top : note he still was alive 12 hours after keeping him in a bag with no water nothing and being half crushed with tweezers bottom: i felt so bad, LUCKILY the clown fish is still alive (the next day) and seems fine, although i can tell the gill is a bit open and a little red inside. i think he will be okay. im guessing i did the wrong thing (As its my first salt water tank and never experienced it) i have a 90 litre (plus sump) tank with live rock and 2 clowns in it.