ya peacocks love to burrow (could be dead) same issue with my khuli loaches never emerged unless I sometimes picked up the decor to suck some poop but in the dead of night if I walk by my tank I sometimes saw it. Tire tracks don't borrow but they get around 2 ft long so pay attention to the amount of space down at the bottom of ur tank with a pleco, bgk (hopefully), featherfin, a catfish I think u mentioned sun?, and a peacock eel.
Also I will show u some pics when my camera charges (been ages since I've used it)