Roe is the term for female fish eggs (hard roe) or the milt of male fish (soft roe). Most fish roe is edible. Some popular roes come from sturgeon, carp, herring, mackerel, lumpfish, perch, salmon, and whitefish. Roe can be found fresh, frozen, and canned. Fresh roe should have a clean smell and look moist and firm. Salting roe turns it into caviar.