somethings eating my fish!

[Godfry]

http://canreef.com/vbulletin/attachm...1&d=1182707955
P6232665.jpg I was just wondering if anyone has seen this happen before, what the heck it is that did this.The thing looks like a type of aptaisia but does'nt spread like the other type I killed off in my tank,so I kept this one until I woke up to this. I hope the pic worked, first time posting one.