Members of this often-colourful family tend to have distinctive pointed snouts, big eyes and thick lips, which gave rise to the old name of ‘sweetlip’. They are one of the versatile hermaphrodite species, starting their mature life as females, later changing to males. About 40 species inhabit the tropical to temperate coastal waters of the Indo-west Pacific and West Africa, with over half of them found in Australian waters. They are mostly caught off northern Australia, mainly by trawls, traps and lines.
The most common commercially-caught emperors in Australia are:
Spangled Emperor (Lethrinus nebulosus and Lethrinus sp.) are the largest and most sought after of the Emperor family. There are two fish marketed under this name, Greater (L. nebulosus) and Lesser Spangled Emperors; they both have yellowish skin with pale blue markings but the Greater has more pronounced blue lines on the face where the Lesser has bluish-brown spots and streaks.
Redspot Emperor (Lethrinus lentjan) is distinguished from other Emperors by the bright red spot on its gill flap near the pectoral fin. It is one of the smallest emperors, averaging about 600g.
Redthroat Emperor (Lethrinus miniatus) is named for its extensive bright red markings; it has the whitest flesh of all the Emperors.
Other Emperors occasionally seen in retail shops or harvested recreationally include:
Longnose Emperor (Lethrinus olivaceus), the most slender and least colourful of the Emperors, with its olive-grey skin. Grass Emperor (Lethrinus laticaudis), which most closely resembles the larger Spangled Emperors. The smaller Variegated Emperor (Lethrinus variegatus) and Threadfin Emperor (Lethrinus genivittatus), which commonly reach about 25cm and school in seagrass and weed. The colourful Orangespotted Emperor (Lethrinus erythracanthus), a larger, solitary fish found near outer reefs. And a group of fish all marketed under the generic name Seabream, which lack the long snouts of other Emperors and so, despite their big eyes and thick lips, more closely resemble Bream than other Emperors; Robinson's Seabream (Gymnocranius grandoculis) is the most common.
Emperors are sold whole (gilled and gutted) and in fillet form. In whole fish look for lustrous skin, firm flesh, and a pleasant, fresh sea smell. In fillets, look for yellowish-white, firm, lustrous, moist flesh without any brown markings or oozing water and with a pleasant fresh sea smell (Seabream can occasionally have a distinctly iodiney aroma).
Make sure whole fish is scaled, gilled, gutted and cleaned thoroughly. Lay whole fish or fillets, in a single layer on a plate and cover with plastic wrap or place in an airtight container. Refrigerate for up to 3 days or freeze whole fish for up to 6 months, and fillets for up to 3 months, below -18ºC.
Emperors are suitable for a wide range of cooking styles, they can be steamed, poached, deep-fried, pan-fried, stir-fried, baked, braised, grilled, or barbecued. They are a good fish to cook whole, either plate-sized or larger to feed a group. The firm flesh lifts easily from the bones when cooked and also holds together well in soups, curries and casseroles or cubed for kebabs. Their firm, moist flesh has a mild, slightly sweet flavour, low oiliness, large flakes and few bones, which are easily removed. The thick skin is usually removed. The bones make excellent stock. Score large whole fish at the thickest part of the flesh and cut thick fillets into serving-size portions to allow even heat penetration.
When is an Emperor not an Emperor?
When it’s a Tropical Snapper (Lutjanus species). Despite the best efforts of the Australian Fish Names Standard, many names can still be confusing. Red Emperor is one obvious example, despite the ‘Emperor’ name it’s actually a member of the, unrelated but similar, Tropical Snapper family, which also includes Mangrove Jack and Goldband Snapper.