Mackerel fish, sometimes indicating the fish has vertical stripes similar to a scombroid mackerel: By extension, the term is applied also to other species such as the mackerel tabby cat, and to inanimate objects such as the altocumulus mackerel sky cloud formation. Most mackerel belong to the family Scombridae, which also includes tuna and bonito. Generally mackerel are much smaller and slimmer than tuna, though in other respects they share many common characteristics. Their scales, if present at all, are extremely small. Like tuna and bonito, mackerel are voracious feeders, and are swift and manoeuvrable swimmers, able to streamline themselves by
Spotted sand-diver Spotted sand-diver The spotted sand-diver ("Trichonotus setiger") is a perciform fish in the family Trichonotidae. "T. setiger" is the type species of genus "Trichonotus". Spotted sand-divers reach a maximum length of . They have 39 to 41 soft dorsal spines. Males can be distinguished from females by their long dorsal fin rays and larger size. "T. setiger" can be found from the Persian Gulf to Queensland and Melanesia Spotted sand-divers occur in large groups where there are steep sand slopes. They hover above clean sandy substrates and dive into the sand when disturbed. The habiata ususally contains some silt. They