i have thank you.I would suggest reading this.
http://www.inmunologia.org/Upload/Articles/6/0/602.pdf
that too.Ooops... while I like that one, this one explains the trade off between immunity and reproduction over a wide variety of animals. Most of it went over my head.
http://icb.oxfordjournals.org/content/46/6/1060.full
I do have a grounding probe in the sump because I have always just done that. I did check with a volt meter and there is no stray voltage. That wasn't too random of a thought... It was one of my first ones.
its totally possible it was a stressor event from malfunction or other, or an introduction. try not to beat your self up.
Heres a weird story. After mostly being home for several months I left for work out of town for six weeks. during that time my talbot damsel, "Little Jerkface", shredded my dsb and burrowed holes all over the tank. I dint know they burrowed in the first place and we had had him for close to a year, and second there were no additions or subtractions or change in feeding schedule as the wife and kid were home to do it. when I got home. He stopped.