sorry about your loss bro. some thing like that happened to one of my red tail payara's, a piece of shrimp got stuck in its throat and died. I tried to save him, he was good till I went to bed but he was dead in the morning.
Moved all the smaller dats to the far right 180g. 15 IT's around 10-11" and 4 NGT's 10-11". I also moved My ST's to the middle 180g with the larger dats. Now I just gotta get another tank set up so I can seperate my smaller dats from my 120gh.
I'll try and take more pics when they get settled in.