My Fish Died!!

[Amandabarrxx]

I have had my 2 goldfish for 2 years now and never had a problem. One was a pearl fish and the other was a fantail goldfish and both got along great with each other. Recently over the last 2 months my pearl fish has been left upside down due to what is most likely swim bladder disease, so first I used disease safe in my tank which failed to work. So I was then given swim bladder treatment which I have been treating my fish with for the last 12 days. I put another dose in the tank last night and when I came home from work both fish where dead( pearl fish lying on the bottom and fantail fish at the surface of water) and filter was making a horrible noise and spitting out what I can only describe as white powder?? Also had what looked like white mucus floating around the tank any ideas as to what has happened??

 

[StrangelyNormal]

Only thing I could possibly think of is some kind of overdose on the goldfish, explaining the white mucous and deaths. I have never heard of those products, although SBD caused by bacterial infection and not overeating is usually fatal and caused by poor water quality. What tank size are they in, and what filters do you have? Also, what's the temperature of the tank?