fear of when i get out of the military and have to move my fish and tanks 6 hours back to houston, also fear of being deployed with my wife tanking care of them. you know its bad when you call her from halfway around the world and the first thing you say is "how are my fish?"
i have a very real fear of getting shocked by my tank [it's happened countless times to me][saltwater+inferior equipment=electrical problems] i try my best to avoid putting my hands into tanks now. even other people's.
Fear of mycobacteria. I have my hands in tanks a LOT. One of my clients just spent a year on antibiotics and had two surgeries from marine mycobacteria. He was knowledgeable enough to tell the doctors to culture for it when he suspected, and that's why he still has all his fingers.