I never have cured sucker eggs, but used to cure salmon eggs for steelhead fishing. Pro-cure makes egg cures that will not only cure eggs but also dye them various colors. Here's the old Borax cure that works well if you want to make a home made cure.
Borax Cure for Skeins
The Borax Cure produces skein eggs that can be stored for long periods of time when frozen. Cut the salmon or trout skein into bait sized pieces (quarter to 50 cent size). In a large plastic bowl mix equal parts of Canning or Kosher Salt, Borax, and Sugar. For the sugar some angler use Brown sugar instead of the commercial white sugar for added scent. Roll the pieces of skein in the cure mixture to coat the entire piece of skein. Then place the pieces in plastic bags. The cured skein will last in the refrigerator for a month or can be frozen for a year or more.