At 03:19 you can see the lower jaw bone hitting the inside upper mouth, preventing him from closing his mouth.
I had this Cichlid for about 2 years. When I got him he was fully grown, so I suspect he was at least 5-6 years old at time of death.
For the past 2 months he had never closed his mouth fully, and constantly moved it from open to half shut.
He ate well, and from the size of him he seemed to be quite healthy. Just last night he took a beating after I re-homed about 35 out of 50 fish from my main tank (obviously upset the previous balance of overcrowding). I put him in a hospital tank but he did within 10 minutes.
I wanted to get a look inside his mouth to see if something was stuck in there, but as far as I could see nothing was. It did look though like his bottom jaw bone would push into his upper mouth when he closed his mouth, preventing him from closing his mouth more than half way. Not sure what caused this?
Obviously a combination of age, the beating, and the move to the hospital tank finished him off. But I wonder if he was just getting old? Thoughts?
I loved this fish, not easy cutting into him but I wanted to try and find out more about why he died.