Hello mate, two days is not really long enough to start worrying, took over two weeks to get my pluero to eat anything, to your question,so he's four inches,i would cram the tank full of plants,plastic is my choice as iam awful with live,but give him plenty of cover, they are predatory so sounds like hes acting normal,they lay in wait,with these guys they will grow at an alarming rate and start to eat you out of house and home,i hope you do realise just how big these guys will grow too?
Try to carry on feeding with bloodworm,also try pellets and chopped prawns, but do not worry just yet,as said though,if food is un eaten then you will need to remove, a little trick i used to get one of mine to eat,was tie a prawn to a peice of fishing line,that way the line will free when foods taken,then i dangled it in the tank,wriggled it around,guess what she took her food that way straaight away,i found with her at first as same with my bycron i have,they wouldnt eat when i was stood there,so that way food was still mid floating when i left room,soon as i was out they took it..