I know saltwater fishes can't survive in freshwater because of osmosis that water would rush into the body of fishes. How about sugar solution? Does sugar solution provide similar conditions as salt water for saltwater fishes?
No, the chloride cells in the gills rely on the relationship between chloride and sodium to remove salts out of the body against the gradient. Switching the environment to sugar would cause the chloride cells to not be able to maintain ionic regulation. See the below link for basic info on chloride cells: https://en.m.wikipedia.org/wiki/Chloride_cell