Indeed, it is if you are among my jewish friends, shellfish and shrimp etc is not allowed per their belief.
as far as muslims go, at most it is makrooh, which in itself is a wishy washy word. There is no agrred upon view of it being haram and it has not been deemed haram in the quran.
and as far as haram things go..
so is facebook 
http://www.paklinks.com/gs/all-views/320458-facebook-haraaaaaaaaaaaaaam.html