To n ije ništa strašno,barem po knjigama.Naime radi se o tzv.englesko govorečoj:black spot disease,koja je prouzrokovana od parazita,a to što se vidi na tijelu su ciste.
"This condition,sometimes known as black spot disease,is produced by matacercarial cysts of a parasitic trematode worm whose ultimate hosts"
a eto:
"Affected fish rarely sport more than a few matacerciriae /ciste/,which do not harm"
A o lijeku ni riječi.