Infestations ... I have been calling them RTD's .... (reef transmitted diseases)
I've been around .... (at pretty much all of the wholesalers in Los Angles. Dont be dirty). Because I have seen so many of the L.A. Wholesalers systems first handed, I dip every coral that comes through our building and highly suggest you do the same. In our holding systems we also keep a 'staff' of clean up animals specifically for removal of problem parasites. Radiant Wrasse, Melanarus, Lettuce Nudi, Sixline Wrasse, etc. to handle common problems.
So many animals go thru the wholesalers, most of them take measures to bleach the tanks that have the fish, but very little is done from what I see to control problems with the corals/inverts. It's impossible for them to properly quarantine corals when a lot of times they don't even make it to the systems before they are snatched up. It is impossible to bleach a coral system - no matter what you do it would mess up the biological filtration and cause more problems. Of course the problem is increasing because nothing can be done about it and the problems sit in the tank and don't get taken care of.
I used to pull sundial snails off incomming zoanthids all the time at one place I used to work. I seriously doubt anyone else did because they kept asking me what I was doing. I found a huge nudibranch problem in one of the soft coral tanks that nobody else had seen or identified.
I've seen multiple nudibranch invasions of various types, red bugs, flat worms, ugly mother-in-laws .... you name it - all at wholesalers.
The LFS should always do some type of dip, always watch their corals for trouble, and most of all - the end user (hobbyist) should very likely practice procedures to quarantine and dip their corals.
