Vasuki was an overzealous flarer and had been blowing out his fins flaring at Barti so I swapped him and Phoenix yesterday and placed Vasuki back in the smaller tank. I guess he didn't approve because I found his shriveled, stiff body underneath the table just a few minutes ago when I came home from school. I buried him in the garden in a patch of shade.
I don't know how he got out. The filter takes up most of the opening in the lid so the gaps shouldn't have been big enough for him to leap out of and the feeding hole is barely big enough for me to stick two fingers through. Otherwise, the tank is practically air tight. Sigh.
SIP my baby boy.