Yeah they were both 13 inches and I usually feed them massivore pellets and they died because my aerator broke down lucky like my endli and ornate survived
There are some cases where some people are not informed that polys breath air, and they fill their aquariums fully to the top, and unfortunately the bichir drowns.
it's most likely nothing to do with them not having enough access to air. Otherwise the ornate and endli would've been dead by now as well. Are there any changes or abnormalities leading up to when they died?