We have two goldfish in a 90L tank. DD accidentally acquired them as tiny tiddlers from a fair a year ago. We didn't think they'd survive but they did and have gone from strength to strength getting large and sleek.
Just got back this evening a found one lying totally dead at the bottom of the tank.
It was fine when they were fed this morning, no sign of sickening for anything. If anything it was the sleeker and fitter looking of the two. Have just given it a look over - can't see any obvious signs of illness - no fungus or weirdness in the fins or scales. It looks perfect. Any ideas about what it could have caused an apparently healthy goldfish to suddenly drop dead?
Plus, now that I look very closely at the surviving goldfish, there is something odd going on around its eyes. Looks like some extra skin around there, with a few tiny bits hanging off. Is this a kind of fungus? What can I do, or is this one doomed as well?