Brad...
I am sure you are pretty bummed about losing your Oscar ...and we all feel for you.
If it is any consolation (or help in any way)...perhaps we can all put our heads together and see what could have possibly caused his death.
Oscars being a full-bodied fish..usually are quite "hardy"....
..but they can get ill just like any other fish. They just hide it well.
Can I ask ?..how did your friend acclimate Gus to his tank?
As Megham said ...if there was a vast difference in PH levels..it could have shocked him.
But there would have to be a HUGE difference.
Say going from a 7.5 to an 8.0 or
vis= versa.. that
wouldn't do it IMO. If you live in the same area...I would think the PH would be fairly the same.
The other thing that seems to stick out in my mind is that you said he was always banging the intake valve.
He either was doing so because of lack of room...poor water quality..or he could of had a bacterial infection...
(external parasites)..and was trying to rid them by rubbing his body against anything he could find.
There are just many factors that could of been at play..and sadly you may never know.
Fish keeping is always a learning experience. Even though I have been doing this for many years..I am still learning things also.
We all have times like these.
If we can learn from it though..then we all benefit.
It is just sad when you lose a fish you have grown so attached to.
