双线若鲹，又称曳丝平鲹、背点若鲹，俗名为甘仔鱼，为辐鳍鱼纲鲈形目鲈亚目鲹科的其中一个种。

本鱼分布在印度西太平洋区，包括红海、东非、马达加斯加、毛里求斯、斯里兰卡、印度、安达曼群岛、马尔代夫、日本、**、中国沿海、菲律宾、印尼、越南、马来西亚、澳洲、所罗门群岛、密克罗尼西亚、瑙鲁、马里亚纳群岛、马绍尔群岛、萨摩亚群岛、复活节岛、加拉巴哥群岛、夏威夷群岛、法属波里尼西亚、新喀里多尼亚、美国加利福尼亚州、墨西哥、厄瓜多尔、巴拿马的沿岸等海域。

The shadow trevally, Carangoides dinema (also known as the shadow kingfish, twothread trevally and Aldabra trevally) is a species of inshore marine fish in the jack family Carangidae. The species is patchily distributed throughout the tropical and subtropical waters of the Indian and west Pacific Oceans, from South Africa in the west to Japan and Samoa in the east, reaching as far south as Indonesia and New Caledonia. It is most easily distinguished from similar species by as series of dark rectangular blotches under the second dorsal fin, giving a 'shadowed' appearance, from which its common name is derived. The shadow trevally is a reasonably large fish, growing to 85 cm in length and at least 2.6 kg in weight. It inhabits shallow coastal waters, including reefs, bays, and estuaries, where it takes small fish and benthic crustaceans as prey. Nothing is known of the species' ecology and reproductive biology. It is of little importance to fisheries, and is occasionally taken by bottom trawls and other artisanal fishing gear.