What is a Remora?

A remora, or suckerfish, is a unique creature found in marine environments. This fish, recognizable for its long, slim bodyline, is most often found attached to larger marine creatures, such as sharks and manta rays. Using a unique sucking organ, remoras can travel for miles attached to a larger host, picking up meals along the way.

There are several different species of remora, most living in tropical or sub-tropical waters. They have been found in more temperate waters, presumably arriving there via the migration of the remora's host animal. There are at least eight known species of the remarkable remora, ranging from the tiny Remoropsis pallidus to the 3 foot (91.44 cm) sharksucker.

Remoras attach to a host via a sucker-like organ on the dorsal fin. This oval disc features slats that allow suction to occur, allowing the remora to latch on by swimming backward to lock the slats down. A remora can detach at any time simply by swimming forward. Although remoras swim quite well, the fish greatly benefits from this easy form of travel as it requires little energy expenditure. In the difficult world of the deep, sometimes the way to survive is by expending the least energy to get the most food.

There is some scientific debate about what remoras eat while riding their larger hosts. While some believe they scavenge for scraps from the host creature's meals, others believe they devour parasites and surface crustaceans that live on the host's skin. Some scientists also believe that remoras increase their symbiotic relationship with a host by living on the host's feces.

Certain species of remora can be quite picky about their host animals. The large sharksucker prefers attaching to sharks, while one Australian species attaches almost exclusively to whales. Other common hosts include dugongs, rays, and turtles. Smaller species may attach to large fish, such as tuna, marlin, and swordfish. Since the hosts seem to tolerate the remoras, it is believed that the suction does not cause discomfort and that the fish may even be beneficial to their hosts by eating parasites.

Remoras may provide unexpected rides themselves, particularly those attached to large rays. In tropical waters where giant manta rays flourish, free divers often take advantage of the remora-ray relationship in order to take a ride themselves. By grabbing onto conveniently attached remoras, divers can go “ray riding,” using the remoras as handlebars to stay attached to the graceful ray.

A remora, also known as a suckerfish, is a small marine fish that forms a symbiotic relationship with larger marine animals like sharks, whales, and turtles. It uses a suction cup on its head to attach to the host, feeding on scraps and parasites without harming the larger creature. This commensal relationship benefits the remora by providing food and transportation.

The remora's suction cup, evolved from a modified dorsal fin, creates a powerful vacuum that allows it to adhere to the host. It consists of a series of slat-like structures that can open and close to create suction. This unique adaptation enables the remora to maintain a strong grip even on smooth surfaces and while swimming at high speeds.

Remoras are generally harmless to their hosts. They do not feed on the host's blood or tissue, but rather on leftover food particles and external parasites. In fact, some hosts may benefit from the cleaning service provided by remoras, which can help reduce the load of harmful parasites on the host's body.

Remoras feed on a variety of food sources, including the scraps of their host's meals, plankton, and small fish. They also consume ectoparasites they pick off the skin of their hosts, which contributes to a symbiotic relationship where the host animal receives a degree of cleaning and the remora gets a meal.

Remoras are not particularly selective about their hosts and will attach to almost any large marine animal that can provide them with food and transportation. They are often seen with sharks, rays, bony fish, sea turtles, and even ships. Their choice is opportunistic, based on the availability of hosts that can offer them the resources they need.

Remoras play a role in marine ecosystems by helping control external parasite populations on their hosts. By feeding on these parasites, they provide a cleaning service that can benefit the health of larger marine animals. Additionally, their scavenging helps in the breakdown and recycling of organic material, contributing to the overall health of the ocean environment.