Live Bug stays in my tank

Question
I have a large (1 inch long)bug in my tank, I kept seeing it and thought it was just my imagenation.  Since I have recently had a stroke everyone thinks I am nuts any way... but I kept telling my family that I am seeing this "Bug" crawling around the rocks in my tank.  Today I fished this thing out of the tank and I was so creeped out by it I could not even kill it.  I put the
@#%&*$# thing in a plastic lunch bag (did not want it getting back out) but now... I know that one means MORE and I do not want another one... what can it be and where did it come form and how do I make sure I do not have another one?
Help... I do not like extra THINGS in my tank... Sheri

Answer
Sheri,
I have enclosed a website that talks about "bugs" found in the tank. See if any of them are the same as the one you removed. The only thing that I know of that can get that long is a tubifex worm. If you do not see the one you have on this website, come back to me and describe it as best you can.

http://www.planetinverts.com/what_is_that_bug_in_my_aquarium.html