Many are quite large – the 400kg Queensland Grouper (Epinephelus lanceolatus) is one of the largest bony fish in the world. Sizes do vary considerably however and some smaller species, such as the Orange Basslet (Pseudanthias squamipinnis) and Swallowtail Basslet (Serranocirrhitus latus), travel around in large schools. Large or small, many live over or among coral reefs, where their bright colours and striking markings act as camouflage.
The most common commercial rockcods in Australia are:
- Bar Rockcod is the marketing name for two similar species which average 1-20kg. They are identifiable by the distinct, dark vertical bands on their grey skin. Epinephelus ergastularius (Banded Rockcod) is found right along the eastern Australian coast and caught mainly off NSW, while the slightly smaller E. septemfasciatus is caught off south-western WA.
- Coral Trout (Plectropomus species) – Ajmong the most prized eating fish in Australia, with lovely firm white flesh and a mild sweet flavour; they average 500g-4kg. Several have individual marketing names, but a number, including Coronation Trouts (Variola species), are usually sold under the generic name Coral Trout; all are distinctive for their red skin with bright blue spots.
- Goldspotted Rockcod (Epinephelus coioides) has distinctive orange-reddish brown spots all over its body and averages 1-25kg. It is found in lower rivers, estuaries and offshore, to depths of 100m, around most of the Australian coast from Perth (WA) north-east to Coffs Harbour (NSW).
- Duskytail Grouper (Epinephelus bleekeri) is brownish-purple and covered with numerous small, yellow, orange or gold spots. While the top of the tail fin is spotted, the lower two thirds are dusky in colour, giving this fish its common name. Other Epinephelus species, including E. morrhua, E. ongus, E. merra and E. heniochus, are sold under the generic name Grouper.
- Yellowspotted Rockcod (Epinephelus areolatus), with distinctive large yellowish-brown spots all over its pale body, is one of the smaller rockcods, averaging 400-800g and only reaching a maximum weight of 1.2kg. It inhabits tropical waters and is caught inshore off far north Qld, NT and northern WA.
- Longfin Perch (Caprodon longimanus), another small rockcod averaging 500g-1kg, has distinctive pinkish-red colouring, which is more yellowish in mature males who also have a prominent black blotch on the dorsal fin. It is found, often in large schools, over reefs off south-eastern Australia.
- Eastern Wirrah (Acanthistius ocellatus) has yellowish-green skin with small blue spots and blue fins, averages 300g-1kg (though it can grow to 4kg) and is found from southern Queensland to northern Tasmania and mainly caught off NSW. A related species, Western Wirrah (A. serratus), is caught from Ceduna (SA) to Kalbarri (WA), while other Acanthistius species occur around Australia and are sold under the generic name Wirrrah.
- Other rockcods occasionally seen in retail shops or harvested recreationally in various parts of Australia include:
- Rankin Cod (Epinephelus multinotatus)
- Sixbar Grouper (Epinephelus sexfasciatus)
- Barramundi Cod (Cromileptes altivelis)
- Blacktip Rockcod (Epinephelus fasciatus)
- Coral Cod (Cephalopholis species)
- Longfin Rockcod (Epinephelus quoyanus)
- Maori Rockcod (Epinephelus undulatostriatus)
- and a number of Aethaloperca and Anyperodon species sold under the generic name Rockcod.
Rockcods 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 white-pink, firm, lustrous, moist flesh without any brown markings or oozing water and with a pleasant fresh sea smell. Species living in estuaries, such as goldspotted rockcod, will often have darker flesh.
Make sure whole fish is scaled, gilled, gutted and cleaned thoroughly. Lay whole fish or fillets in a single layer on a plate or tray 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.
Cooking & Serving
Rockcods are suitable for a wide range of cooking styles, they can be steamed, poached, deep-fried, pan-fried, stir-fried, baked, grilled, barbecued, or eaten raw (sashimi). The firm flesh holds together well in soups, curries and casseroles and can be cubed for kebabs. Their firm, moist flesh has a mild flavour (with smaller specimens being slightly stronger flavoured, and fish from estuaries sometimes having a slightly muddy flavour), low oiliness and large flakes and few bones, which are easily removed. The thick skin is best removed. The bones make excellent stock. Score whole fish at the thickest part of the flesh and cut thick fillets into serving-size portions to allow even heat penetration. The heads of large fish are good eating – especially the cheek meat – and popular for dishes such as fish head curry.
As with so many fish, the common names can lead to confusion. Despite the abundance of ‘cods’ in this family, they are not related to the Gadidae family, of ‘true cods’ from the northern hemisphere. Their firm, white flaky flesh makes them a good substitute in recipes calling for cod and is no doubt what led to their confusing name.