These gorgeous Murray Cod were natural deaths from an aquarium. The cause of death for the larger one (white lid) should be pretty obvious! It was fascinating seeing this appear as I cleared the tissue, as much as it was a little heartbreaking. I am unsure how the other one passed.
Murray cod are a really awesome and unique freshwater species native to Australia. Sadly, due to extreme overfishing and habitat destruction they are now critically endangered in the wild.