I hope you can help me with my sick oscar.
Two of my juvenile oscars have died in the past two months, and I don't know what disease killed them. But I think they're the same illnesses because the symptoms were very similar.
I would notice that they were very healthy about 2 to 4 hours before they started to settle peacefully at the bottom of the tank. Their fins would fold, not the usual healthy spreading of the fins. Their breathing would become fast and shallow, it's as if they're gasping for air, and they can't close their mouth tightly shut. Their mouth would open then close but not tightly closed, like the other healthy oscars. The bigger oscar (3 inches long) died about 4 days later, the smaller oscar (1 1/2 inch long) died the next day. I scooped up the dead body of the bigger oscar from the tank and I touched it, and it was covered with a very slimy substance, possibly mucous.
Now, my other oscar (3inches long) is showing the same symptoms. I noticed this last night. Just 3 hours before it was healthy as an ox. I'm afraid this oscar will die if I won't give it some medication. Problem is, I don't know what sickness this is. I'm sure it's not ich, it's not fungus, it's not fin/tail rot, because physically it looks very healthy. It's behavior and breathing is abnormal. It would fold its fins. Its movements are very slow, just like when an oscar is full. Could over feeding have done this? I fed them first at around 11am, fed them again at 4pm. I give them prawn feeds, a cichlid breeder recommended this to me. He says fish grow bigger when fed with this, and the pet shop owner agrees w/ him. I've been feeding them w/ this since I began this hobby about 2 months now. I wonder if these are cases of indigestion. They're (the one's who died) stomachs look full, eventhough they haven't eaten for days.
Please help me out in any way you can. I don't want to lose a 3rd oscar; I love them too much.

