I have never speared suckers so I can't help you much, but I would use a regular decoy. A decoy attracts all fish not just pike, they also use decoys to spear sturgeon. I think fish see the flash and movement and want to see what it is out of curiosity and/or hunger. I used to bring in perch with my decoy all the time in MT. Up here in AK I have brought in trout, char, landlocked salmon, and stickelbacks. And While I am jigging the decoy they hang out there all day. Dropping eggshells down the hole really brings the fish in too, especially on sunny days. They see all that light reflecting off the shells and come in to investigate. Hope this helps.