nassarius snails are usually great in a tank taking care of unwanted waste and such... What is a sea hare..??? Ive never heard of one, what size is your tank, and how long have you had it set up?
I dont think the Nas. snails could have killed your sea hair. There a harmless snail. The sea hair probly just saw his reflextion in the glass!! There the ugliest things in the world, but there great algea eaters.
Todd
sea hares are not ugly they are cute look like have shrek ears i love my little sea hare.
if you do a search on them you will find pictures i have seen them posted
I'd agree that it is unlikely that your nassarius snails would attack and consume a healthy seahare and I'd also agree that seahares are a touch on the uuuuugly side....