The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
Possibly, I can't recall what parts, but I am pretty sure it is a defense mechanism. They may foul your tank if they die. I would wait on other responses.
I don't know anything about this fish, but my trusted source tells me that it's semi-aggressive and requires a 50 gal tank minimum but says nothing about it being poisonous: