There was some difference in the size of the fish, but overall the fish were believed to be adults. The laboratory is indicating this as the probable cause of the fish deaths, but they are still checking for bacteria and viruses. The fish began dying 5 days ago. My grateful appreciation to all the kind folks in the various Minnesota departments that tried to help me track down the correct information. I am especially indebted to Marilyn Dank and Al Schmidt.
Some species are loricate, and some form colonies.