#scombriformes

Interestingly, the Antarctic Butterfish (Hyperoglyphe antarctica) mainly feeds on one species of tunicate: Pyrosoma atlantica.

Young Centrolophids, such as the Medusafish (Icichthys lockingtoni) and Imperial Blackfish (Schedophilus ovalis), are often found living amongst jellyfish and siphonophores; using the stinging tentacles for protection and also scavenging the remains of their meals.

Meanwhile, the Man-of-war Fish (Nomeus gronovii) (image 3) also lives in the tentacles of the Portuguese Man O’ War (Physalia physalis), but instead feeds on the colony’s smaller tentacles and gonads. The fish's agility, high vertebrae count, and specialized skin features allow it to avoid the siphonophore’s toxins.

The Bigeye Squaretail (Tetragonurus atlanticus) avoids exploitation by being toxic to humans.

The Silver Pomfret (Pampus argenteus) (image 2) is an especially popular fish in Kuwait, and is one of the most expensive types of fish in the market. The Kuwaiti government regularly bans the fishing of the Kuwaiti type to allow the vulnerable fish to reproduce.

Bluefish (Pomatomus saltatrix) are known to be voracious predators, and will enter feeding frenzies even after it seems they’ve eaten their fill. They will sometimes chase small fish through the surf zone, attacking schools in very shallow water, churning the water like a washing machine. This behavior is sometimes referred to as a "bluefish blitz". Wading or swimming among feeding bluefish schools can be dangerous. In July 2006, a seven-year-old girl was attacked on a beach, near the Spanish town of Alicante, allegedly by a Bluefish.

The Ragfish (Icosteus aenigmaticus) is a mysterious fish, named because its skeleton is mostly cartilage and its skin has no scales, giving it a floppy raglike appearance. They mainly eat jellyfish. Ragfish are rarely seen and little is known about them, but they are quite large fish that can grow up to 2 m (6.6 ft) long.

Australian Salmon (genus Arripis) form immense schools with hundreds to thousands of individuals, as both adults and juveniles. The fish hunt en masse by co-operatively chasing baitfish up to the surface. This herding technique is exploited by seabirds which are quickly attracted to, and feed upon, the foaming mass of fish at the surface. The baitfish made available by the Australian Salmon's herding behaviour may be important to the reproductive success of winter-nesting birds: the decline of Australian Salmon stocks has evoked concern for these bird species, some of which are endangered, such as the Fairy Tern (Sterna nereis).

The Swallowers (family Chiasmodontidae) seem designed with voraphiles in mind (sorry). These palm-sized, deep sea fish have highly distensible stomachs that allow them to swallow prey over twice their length and 10 times their mass. Black Swallowers (Chiasmodon niger) have been found to have swallowed fish so large that they could not be digested before decomposition set in, and the resulting release of gases forced the swallower up to the ocean surface. This is, in fact, how most known specimens come to be collected. In 2007, a Black Swallower measuring 19 cm (7.5 in) long was found dead off of Grand Cayman. Its stomach contained a Snake Mackerel (Gempylus serpens) 86 cm (2.8 ft) long, or four and a half times its own length. While surprising for us, this adaptation allows these fish to take advantage of whatever food they can, whenever they can, in an environment where food is scarce.

Unlike most other Actinopterygiians, Scombrids (tunas, mackerels, bonitos, and the Butterfly Kingfish) are endothermic, and are able to raise their body temperature to achieve thermoregulation. They also have an organ which heats their brain, derived from the lateral rectus eye muscle.

While generally known only for their meat, Tunas (tribe Thunnini) are large, powerful, pack-hunting, apex predators of the open sea, that are known for their speed and agility. The Atlantic Bluefin Tuna (Thunnus thynnus) (image 1) can grow up to 3.84 m (12.6 ft) long and weigh up to 680 kg (1,500 lb). Very large specimens may be up to 50 years old.

The commercial importance of the Atlantic Bluefin Tuna has led to severe overfishing. The International Commission for the Conservation of Atlantic Tunas affirmed in October 2009 that Atlantic Bluefin Tuna stocks had declined dramatically over the last 40 years, by 72% in the Eastern Atlantic, and by 82% in the Western Atlantic. A UN proposal to protect the species from international trade was voted down (68 against, 20 for, 30 abstaining). However, since then, enforcement of regional fishing quotas has led to some increases in population. As of September 2021 the Atlantic Bluefin Tuna was moved from the category of Endangered to the category of Least Concern on the IUCN Red List of Threatened Species. However, many regional populations are still severely depleted, including the western stocks which spawn in the Gulf of Mexico.

The high concentration of omega-3 polyunsaturated fatty acids in the flesh of the Slender Tuna (Allothunnus fallai) caused the CSIRO to declare that the the species was Australia's healthiest seafood dish.

The Southern Bluefin Tuna (Thunnus maccoyii) is classified as endangered, but it is still fished for commercially (with quotas that are not always enforced) mainly in Australia and also in Japan, targeted by recreational and game fishers in Australia, and is also the target of several annual fishing competitions. In Australia, the Southern Bluefin Tuna is listed as “Conservation Dependent” under the EPBC Act. This listing allows for the commercial exploitation of the species, despite their accepted global status as an over-fished, endangered species. Southern Bluefin Tuna is considered a gourmet food, and is in demand for use in sashimi and sushi. As with all seafood, it is important to know what you are buying so as not to increase demand for the overexploitation of endangered species.

The deep-sea Longfin Escolar (Scombrolabrax heterolepis) is unique among fishes for having several of its vertebrae hollowed out and filled by evaginations of the gas bladder.

One of the largest deep-sea fish, the Oilfish (Ruvettus pretiosus) can grow to a length of 3 metres (9.8 ft), though most do not exceed 1.5 metres (4.9 ft). They are named for their extremely oily flesh, which makes the meat act as a laxative if consumed in high quantities. The flesh of Oilfish is rich in taste and can be substantially cheaper than that of other fish species, leading to some vendors intentionally mislabelling it as “whitefish”, butterfish, or cod. The consumer may then eat larger servings than recommended, unaware of the laxative effect, and suffer from diarrhea. Among fishermen, it goes by the name Xoba in Praia and Cagazeite, which means "shit out oil" in São Vicente. In January 2007, ParknShop, a supermarket chain in Hong Kong, admitted to selling mislabeled Oilfish in their stores. Over 600 people became sick as a result, suffering from stomach pain and diarrhea.

The Snoek (Leionura atun) is a near apex predator, only preyed on by Brown Fur Seals (Arctocephalus pusillus) in South Africa. They hunt in schools, and are reputed to attack anything that moves near them in the water.

The Silver Scabbardfish (Lepidopus caudatus) is known to strand itself in winter months, likely due to being caught in currents when the fish migrate closer to shore for spawning. It is a traditional food for the Māori people of New Zealand, known by the name Pāra. The fish was not typically caught, but eaten as a supplementary food when schools washed ashore. Māori traditionally believed that strandings were caused by the fish chasing the Moon, while early European settlers believed that the fish purposefully chose to end their lives by stranding themselves.