HusbandryCaranx ruber, also called Black-throated Blue trevally. Bar jack, black jack, blue runner, blue-striped cavalla, crevalle jack, crevalle, greenback, jack, neverbite, passing jack, point nose, rainbow crevalle, red jack, runner, skip jack, and skip-jack are further common English names. They are found from New Jersey through Bermuda, in most of the Gulf of Mexico, the Caribbean, and the West Indies. It is uncommon in the northern Gulf of Mexico. There has been an unconfirmed capture of a bar jack in Rio de Janeiro, Brazil. It is the most common Caranx in the West Indies and Bahamas.
The bar jack usually lives in clear, shallow waters over coral reefs. It is typically found in schools varying in size from a few fish to many. Occasionally the bar jack is seen swimming alone. Juveniles may be observed under patches of Sargassum mats. Schools of larger fish also occur under large Sargassum on occasion.
Caranx ruber is similar in color to the Caranx hippos. Both have a silvery body, with a grayish tint above and white below. It has a dark bar, for which it is named, that extends from the snout, along the back, and through the lower lobe of the caudal fin. The juveniles have six bars which appear when the fish are just over 0.75 inches (19 mm) in length. These bars converge into a single bar by the time the fish reaches a length of 2.36 inches (60 mm). The bar jack sometimes turns a bronze color when feeding on the ocean floor.
The Black-throated Blue trevally reached a final height of 50 cm, but usually remains well below (about 40 cm). It has, in terms of food, a "dual mode". Although the main food of other fish, shrimp and invertebrates exists (even coral heads), they also take food from or on the ground. In particular, already older juvenile animals often follow rays and other bottom-feeder "and mimic their feeding behavior. Animals in the early juvenile stage, zooplankton eat and take their food mostly to near the surface.
Aquaristic the fish is already uninteresting because of its final size.
Order - Perciformes
Family - Carangidae
Genus - Caranx
Species – C. Ruber