Here's what I have in my tank. I've removed at least 20 of these in the last 3 months. Some way bigger. I never got stung, but don't want to. Caught this guy stinging a nassarius snail, but he got away. Weird blue color, eh?
Tom
Actually if you go to his web site you will see it all laid out in other pictures...
The post I have the pictured linked is directly to his site. You can Google to find it or press the quote buttom and see the link there for the site URL in post 13.