Scombroidei

Unlike many other Perciformes, this suborder does not have a protrusible premaxilla. But it's okay, they have lots of other cool aspects to make up for it.

Sphyraenidae: Barracudas

Instantly recognizable by their protruding lower jaw and loads of teeth, there is only one genus, Sphyraena. They have a long, streamlined shape with widely spaced dorsal fins, making them perfect for quick attacks to ambush their prey.

Gempylidae: Snake Mackerals

Similar to barracudas, these fishes have a protruding lower jaw but have a long first dorsal fin that spans most of the body.

Trichiuridae: Cutlassfishes

No, that's not a swimming sword...that's a cutlassfish! Also with a protruding lower jaw and sharp fanglike teeth, these fishes have two long dorsal fins with an anal fin that matches the length of the second dorsal fin. They also have a tiny to absent caudal fin, and often lack pelvic fins as well.

Scombridae: Mackerals, Tunas

One of the most famous families in the ocean, the tunas! They are built for speed, with a fusiform (streamlined) body for open water swimming. The dorsal fins can be depressed into grooves, and there are "finlets" behind the dorsal and anal fins to reduce drag. Some species are able to generate heat to warm the swimming muscles, but they are not officially considered endothermic. Many fishes are called mackerels, but the true mackerels are found in the tuna family. Some interesting species are mentioned below.

• Wahoo (Acanthocybium solandri): I just think this is a great name. It can be found at some restaurants and is also considered a good sport fish.
• Yellowfin (Thunnus albacares) and Bigeye (Thunnus obesus): Both species are known as "ahi" and can grow up to 180kg. Both are used for sushi and other foods and are considered to be unsustainable foods.
• Albacore (Thunnus alalunga): Familiar to many as white meat tuna. Strangely, the right gonad is larger/heavier in most individuals.
• Other common food fishes include the Atlantic Bonito (Sarda sarda) and the Atlantic Mackerel (Scomber scombrus).

Xiphiidae: Swordfishes

Huh, it's called a swordfish...I wonder why? Probably because of the elongated bill which comes to a point. There is only one species, Xiphias gladius. It lacks scales and pelvic fins, and can grow up to 4.5m. They are considered one of the fastest fishes, though its top speed is unknown. It uses its streamlined shape to catch prey, but uses its bill to slash at fish to wound or stun before eating. Swordfish is a popular game and food fish.

Istiophoridae: Billfishes

Although to the untrained eye, billfishes look the same as the swordfish, the fish expert notes many differences. Unlike the swordfish, billfishes maintain scales in adulthood, have pelvic fins, and have teeth in their jaws. Unlike the swordfish with its one-keeled tail, billfishes have two keels. The dorsal fin is often elongated, stretching along the body. Billfishes are also popular game and food fishes.