Remoras (suckerfish)
Echeneidae
Often hitching a ride under sharks, rays, turtles or even ships. Look twice, because some remoras also swim free near reefs.
Varies by species: each remora species is assessed on its own. The common remora is Least Concern.
Photos show the species, not always the places on this page.
Length
Varies by species. The live sharksucker is usually about 66 cm (2.2 ft) and reaches about 1.1 m (3.6 ft); the manta remora reaches only about 30 cm (1 ft)
Weight
Varies by species and not reliably measured for most. The live sharksucker reaches about 2.3 kg (5.1 lb)
Next to a person
Common reef sharksuckers are often about forearm to arm length; remoras on mantas can be hand-sized
What it eats
A mix of small fish, scraps from their host's meals, parasites picked from the host and sometimes host waste. The diet changes with species and age.
Around people
Harmless
How it lives
Remoras hold on to other animals for a while with a sucker disc on top of the head, which is a changed back fin. Their hosts include sharks, rays, large fish, sea turtles, whales, dolphins and even ships. The live sharksucker often swims free near reefs, while the whalesucker (Remora australis) rides only on whales and dolphins.
Where it goes
Remoras travel with their hosts, so where they go depends on which animal they ride. Some species, like the live sharksucker, also leave their host and swim free near reefs for a while.
We only draw a journey on the map when scientists have tracked it or clearly documented it. For this animal we have not found one yet.
Populations
Remora species are linked more to their hosts than to places. The live sharksucker is the common one on sharks and rays in tropical waters worldwide; Remora australis rides mainly on whales and dolphins, R. albescens mainly on mantas, and R. osteochir mainly on billfishes. Which remoras you find depends on which hosts are present.
Meet it respectfully
Watch only. Never pull remoras off their hosts, and never feed or handle them. A live sharksucker may briefly attach to a diver's leg; stay calm and gently move away. The rules for the host animal, like distance and no touching, still apply.
Fun fact
Tap the bulb to light it up.
The sucker disc is a changed back fin. Soft plates and a fleshy rim hold on with friction and suction.
Remoras are not simply parasites or simply cleaners. They eat a mix of food, and what they eat changes by species and age.
In a field study on blue whales, remoras sat in calmer water zones on the whale's body, which cut their drag by about 71 to 84%.
In a computer model of a shark, riding on the back cut a remora's drag by about 54 to 69%.
Remoras (suckerfish) in the Ocean Atlas
Places we have researched where this animal is recorded. It is never guaranteed, and some places are for watching from the boat only.
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Facts checked 26 September 2026. Photos: Unsplash licence, or Creative Commons as shown on each photo.
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