Masago is capelin roe — the tiny, matte, pale-orange eggs of the capelin, a small cold-water smelt of the North Atlantic and Arctic seas, salt-cured and usually tinted a brighter orange for the table. Each egg is a soft bead only about 0.5–1 mm across, similar in size to flying-fish roe (tobiko) but softer, moister and paler, giving a gentle, sandy, faintly popping bite rather than a crisp crackle, and a mild, salty-sweet, clean-marine taste. It is a workhorse of the modern sushi bar — the inexpensive orange roe folded into spicy-tuna and California rolls, coating inside-out maki, spooned into gunkan sushi and stirred through spicy mayo — and it appears widely across Nordic and Icelandic cooking, where the same capelin roe (Icelandic loðnuhrogn) is sold as a creamed or seasoned spread. Because it is cheaper, softer and paler than the flying-fish roe it resembles, masago is the roe most often dyed and substituted for tobiko, and the two are constantly confused; it is distinct from both tobiko and from the whole capelin fish itself, which is eaten grilled, dried and (roe-laden) as the Japanese shishamo-style delicacy.