One of the best generalized references would be "The Manual Of Fish Health" by Chris Andrews on Tetra Press
Manual Of Fish Health - Andrew, Chris (Never buy Geek Books New) Someone else's wife has already tossed them out !!!
Other than that if you'd like me to disseminate 40 years in the hobby, 9 years in College, and 21 years in the industry I'm afraid you've caught me unprepared. It was hard enough cramming all that in there. Digging it back out gets a bit sticky !

HTH. Prof M