What is "rock cod"

Rockfish \Rock"fish`\, n. (Zo["o]l.)

1. Any one of several California scorp[ae]noid food fishes of the genus Sebastichthys, as the red rockfish ( Sebastichthys ruber). They are among the most important of California market fishes. Called also rock cod, and garrupa.

2. The striped bass. See Bass.

3. Any one of several species of Florida and Bermuda groupers of the genus Epinephelus.

4. An American fresh-water darter; the log perch.

   Note: The term is locally applied to various other fishes.

Cod \Cod\, n. [Cf. G. gadde, and (in Heligoland) gadden, L. gadus merlangus.] (Zo["o]l.) An important edible fish ( Gadus morrhua), taken in immense numbers on the northern coasts of Europe and America. It is especially abundant and large on the Grand Bank of Newfoundland. It is salted and dried in large quantities.

Note: There are several varieties; as shore cod, from shallow water; bank cod, from the distant banks; and rock cod, which is found among ledges, and is often dark brown or mottled with red. The tomcod is a distinct species of small size. The bastard, blue, buffalo, or cultus cod of the Pacific coast belongs to a distinct family. See Buffalo cod, under Buffalo.

Cod fishery, the business of fishing for cod.

Cod line, an eighteen-thread line used in catching codfish.
--McElrath. [1913 Webster] ||

The rock cod (Lotella rhacina) is a temperate fish found off the coasts of southeastern Australia, Tasmania, the Great Australian Bight and northwards up the south western Australia coasts. They are also found around the coasts of New Zealand and California. They belong to the family Moridae and are not related to the true cods (genus Gadus). They are also known as beardie in Australia.

Rock cod are yellow-grey to red-brown with white fin margins. They have chin barbels. They may grow up to 50 cm in length. They are found in caves in bays and coastal reefs. They are frequently found inshore and inhabit shallow waters in the continental shelf with typical depth of 10 to 90 m.

Many other fish are sometimes referred to as rock cod, but most are unrelated to the cod family, and are better known as groupers.