<a href=showthread.php?s=&postid=8054516#post8054516 target=_blank>Originally posted</a> by phender
Even the large ones usually don't bother things unless they are already dead or dying.
I just noticed 3 giant ones in my 55 gal that went after a disgarded silverside, that have been there for at least 3 years and I haven't noticed them doing any damage.
I'm sure you know not to touch them with your bare hands. I accidently touched a tiny one a few weeks ago while taking algae out of my fuge. Although I usually don't have much of a reaction, this one raised a blood blister on my finger the diameter of a pencil that lasted about a week.