What is a Lanternfish?

Lanternfish are small, deep-sea fish that belong to the family Myctophidae. There are many genera of lanternfish, with hundreds of species between them. In general, their bodies are slender with silvery scales and large eyes. All but one species of fish in the Myctophidae family have light-producing organs called photophores, hence the common name lanternfish. These organs emit a weak blue, yellow, or green light that is assumed to be used to communicate. Lanternfish are extremely important to the ecosystem of the ocean, with whales, dolphins, and sharks preying heavily upon them.

While the scales of lanternfish are generally silver, the fish can be tinted other colors, such as blue, green, or black. Light-colored species are typically found nearer to the surface, while brown or black fish are located deeper in the ocean. The length of the fish also varies, but they are normally somewhere between 0.8 inches and 1 foot (2 to 30 cm) long. Photophores, the light-producing organs the fish are known for, grow from various places depending on the species, but they are normally on the head or body rather than the fins or other areas.

Myctophidae fish in general are found in ocean waters all over the world, including the South Pacific, South Atlantic, and Indian Oceans. They are in abundance in most places, unlike their relatives in the family Neoscopelidae. The fish belonging to Neoscopelidae are only found in tropical and subtropical waters, and they are similar in appearance to the fish in Myctophidae. In fact, a particular species of the Neoscopelidae family, Neoscopelus macrolepidotus, even shares the common name, lanternfish.

These fish are some of many that create the deep scattering layer, also known as the false bottom, which refers to a layer of live fish in the ocean. This layer was discovered using sonar technology. In the past, it was often mistaken for the ocean floor, but researchers became confused when the supposed ocean floor rose toward the surface somewhat in the evening, and sunk again once morning approached. Eventually, it was theorized and confirmed that the false bottom consists of marine animals.

Even though lanternfish are hardly rare, little is known about many species. This is primarily because they are deep-sea fish that were not discovered until the mid 1800s, at the earliest. Some species were not discovered until the 1950s, and researchers are still gathering information on their migration and behavior patterns, as well as how they communicate.

Lanternfish are small, bioluminescent fish belonging to the large family Myctophidae. They are found in oceans around the world, typically dwelling in the mesopelagic zone at depths of 200 to 1,000 meters. During the day, they remain deep underwater, ascending to shallower depths at night to feed.

The lanternfish uses bioluminescence for various purposes such as camouflage, communication, and attracting prey. Their bodies are equipped with light-producing organs called photophores, which help them blend into the faint light from above, confusing predators and making it difficult for them to be seen from below.

Lanternfish are generally small, with most species measuring between 2 to 15 centimeters in length. Despite their diminutive size, they play a significant role in the marine food web, serving as a crucial food source for larger predators like whales, seals, and tuna.

Lanternfish are opportunistic feeders, primarily consuming plankton, small crustaceans, and other tiny marine organisms. Their nightly vertical migrations to shallower waters are partly driven by the pursuit of these food sources, which are more abundant closer to the ocean's surface.

Lanternfish are incredibly important to ocean ecosystems, forming a vital link in the marine food chain. According to scientific estimates, their global biomass is extremely high, potentially exceeding 600 million metric tons. They are a key prey species for many marine predators and play a role in carbon cycling through their daily migrations.

Lanternfish, like many marine species, are affected by environmental changes, including ocean acidification and climate change. Their numbers can also be impacted by overfishing, as they are caught incidentally in nets targeting other species. However, they are not currently classified as threatened due to their vast population and wide distribution.