The giant trevally (Caranx ignobilis), also known as the lowly trevally, barrier trevally, giant kingfish or ulua, is a species of large marine fish classified in the jack family, Carangidae. The giant trevally is distributed throughout the tropical waters of the Indo-Pacific region, with a range stretching from South Africa in the west to Hawaii in the east, including Japan in the north and Australia in the south. Two were documented in the eastern tropical Pacific in the 2010s (one captured off Panama and another sighted at the Galápagos), but it remains to be seen if the species will become established there. The giant trevally is an apex predator in most of its habitats, and is known to hunt individually and in schools. The species predominantly takes various fish as prey, although crustaceans, cephalopods and molluscs make up a considerable part of their diets in some regions.

You may have heard how some anglerfish reproduce via the males fusing their bodies to the females' until they essentially become one; the male loses his eyes, fins, teeth, and some internal organs and, from that point forward, lives off of the female, providing sperm when she's ready to spawn. Those fish are members of the suborder Ceratioidei, [or] deep sea anglerfishes, in which some species are known to reproduce by that means. Still, that's not the norm for those fish—scientists have so far only found parasitic males in 5 of 11 ceratioid families. (censored because scary)

The glassy fish is a small species of fish known for its striking transparent or translucent flesh. The body adaptations of the fish are see-through and colorless and one can easily spot the bones and internal organs of the fish with the naked eye. Indian glassy fish sold to hobbyists have often been "painted", which involves injecting coloured dye into the fish's transparent tissue to make them more attractive to hobbyists. These coloured fish are often called "disco fish". Inexperienced fishkeepers are often tricked into believing such fish are natural or that the process is painless and causes no harm.

The smallest shark, a dwarf lantern shark (Etmopterus perryi) is smaller than a human hand. It's rarely seen and little is known about it, having only been observed a few times off the northern tip of South America at depths between 283–439 meters (928–1,440 feet). Like other lantern sharks, the dwarf lantern shark has light-emitting organs called photophores along its belly and fins. These help them camouflage when they feed in shallower water: the lit-up belly blends in with sunlight streaming down from above. In darker water, the light attracts smaller animals, which the shark preys upon. It also has big eyes (for a shark) to help it see in the mostly-dark waters of the ocean's twilight zone.

Vendace is the rarest freshwater fish in Britain, found only in Derwentwater in England's Lake District. A 2008 survey found that a Bassenthwaite Lake population was now extinct. Scotland once had two vendace populations – in Mill Loch and Castle Loch – but both are now extinct. To safeguard the species, fish from Bassenthwaite and Derwentwater were translocated to two bodies of water in the Scottish Borders in the mid-1990s. Vendace were introduced from Bassenthwaite to Loch Skeen and from Derwentwater to Daer Reservoir. Both introductions were successful and this species has become established in both locations. Another translocation of vendace from Bassenthwaite to Loch Earn (Perthshire) was also carried out in the 1990s. A population has become established there, but is present in low numbers.

While diving in tropical waters, you may come across what appears to be a bed of seagrass gently moving with the current. But look more closely—you may actually be swimming among a colony of spotted garden eels (Heteroconger hassi), slim and straw-like fish often mistaken for plants, which live the majority of their lives partially embedded in the sea floor. One of many species in the subfamily Heterocongrinae, spotted garden eels live in areas with strong currents, where they sway together in large groups, feeding on passing zooplankton; there can be hundreds to thousands of eels in a single colony. Garden eels may be small compared to other eel species (only half an inch in diameter), but what they lack in size, they make up for in muscle. H. hassi uses its stiff, muscular tail to dig into the sandy seafloor, then secretes a slimy mucus that acts like cement to keep its burrow from caving in. When alarmed, garden eels withdraw tail-first into the holes they've created in order to avoid predators. Shy and cautious, they will slowly extend their heads out of the burrow once the danger has passed.

British lawyer Victoria Evans battled high winds, big waves and sleep deprivation to record the fastest female solo row across the Atlantic Ocean. After setting off from Tenerife, Spain, on February 11, the 35-year-old covered 4,740 kilometers in 40 days and 19 hours before finally reaching land in Barbados. Despite experiencing extreme conditions and encountering multiple problems along the way, Evans broke the previous world record by over eight days.

The Quilotoa Crater we see today sits within an extinct volcano and was formed during a massive volcanic explosion centuries ago. The crater was formed when the volcano's massive cone collapsed in on itself, leaving the crater in its place, which became a lake when it filled with water. The last major eruption here occurred in 1280 AD. This eruption was one of the most powerful recorded on Earth in the last 1000 years, with volcanic flow reaching all the way to the Pacific Ocean!

A highly valued food fish, the turbot lives along sand and gravel shores. It is a left-sided flatfish, with its eyes normally on the left side of the head, and it is scaleless, though its head and body are studded with numerous bony knobs, or tubercles. It reaches a maximum length of 1 metre (40 inches) and weight of about 25 kilograms (55 pounds). Colour varies with the surroundings but is usually gray brown or light brown with darker markings.

Sabertooth fishes (also spelt sabretooth) are small, fierce-looking deep-sea aulopiform fish comprising the family Evermannellidae. The family is small, with just eight species in three genera represented; they are distributed throughout tropical to subtropical waters of the Atlantic, Indian, and Pacific Ocean. These fishes are appropriately named for their oversized, recurved palatine teeth redolent of the saber-toothed cats. Sabertooth fish are usually a drab, light to dark brown when preserved; however, a brassy green iridescence is seen on the flanks, cheeks, and ocular region of well-preserved specimens. The naked skin is easily torn. The Atlantic sabertooth (Coccorella Atlantica) is the largest species, at up to 18.5 cm standard length.