I HAVE 998 AND 859 AND THEY PICK CRAPPIES UP GOOD,THE 859 DO REAL WELL,ARE U SURE U HAVE GONE OVER ANY,THE 859 WILL DRAW EACH LIMB AND THE FISH THAT ARE RELATED TO IT,BEEN GOING OVER BP LAST 2 MONTHS AND IF 859 DO NOT SHOW FISH I KEEP GOING,ALSO GOT WHERE I CAN TELL IF THEY ARE SMALL AND IF SO I KEPT GOING,BUT OUR LAKE IS FULL OF CRAPPIES.BOTH OF THESE UNITS ARE MOUNTED AT BACK,ANOTHER 2D DI AT FRONT