Depth
Serpula · Worms & Tube Worms

Red Tubeworm

Serpula vermicularis

0-40m
Depth Range
Variable
Max Size
Mediterranean
Distribution
0-40m
Depth Range
Variable
Max Size
Reef & Open
Habitat
Carnivore
Diet
Solitary
Social
LC
IUCN Status
Kingdom Animalia
Phylum Annelida
Genus Serpula
Species vermicularis

Polychaete

Identification & Biology

  • IdentificationA small tube worm with a hard, white, calcareous tube that is irregularly coiled or sinuous on rock surfaces. The worm extends a small fan of red to orange radioles and has a conical operculum (plug) for sealing the tube opening.
  • SizeTube length up to 7 cm. Fan diameter up to 1.5 cm.
  • Social HabitCan be solitary or gregarious, sometimes forming dense masses of intertwined tubes on rock surfaces. The accumulated tubes create reef-like structures in some areas.
  • HabitatAny hard surface: rock, shells, pier pilings, boat hulls, and other organisms. A common fouling organism.
  • Depth0 to 100 m. Found throughout its depth range.
  • Feeds OnPlankton and suspended organic particles captured by the radioles.
  • DistributionWorldwide in temperate and tropical seas. Very common in the Mediterranean and Maltese waters.
  • DescriptionSerpula vermicularis is one of the most common and widespread tube worms in the world. Its hard, white, calcareous tubes are found on virtually every hard surface in Mediterranean waters. In some areas, the accumulated tubes of many individuals form substantial reef-like structures that provide habitat for many other organisms. The small red fan is attractive but retracts instantly at the slightest water movement.

Range

Habitat & Distribution

Found across the Mediterranean, inhabiting reef & open environments. Active from the surface down to 40m depth.

Where Malta divers have spotted this species

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Sightings are logged by divers using our What Did You See? dive-log tool. View the full live sightings map.

Detail

Preferred Environment

Reef & Open habitats, typically at depths of 0-40m. Most commonly encountered by divers at the shallower end of its range.

Encounter Tips

Best approached slowly and calmly. Avoid casting shadows directly over the animal. Neutral buoyancy and patience increase encounter success significantly.

Red Tubeworm species card

Biology

Behaviour & Diet

Feeding Strategy

Extends twin sets of bright red, feathery gills from the opening of its calcareous tube to absorb dissolved oxygen and filter fine organic particles from the water. The gills also function as feeding structures, trapping bacteria and microalgae.

Filter feeder

Reproduction

Releases eggs and sperm from the tube opening into the surrounding water for external fertilisation. Larvae are planktonic for a short period before settling and secreting their own calcareous tube on hard substrate.

Broadcast spawner

Behaviour & Defence

Builds a hard, white calcareous tube permanently cemented to rock that provides strong physical protection from predators. The worm can retract fully inside and seal the opening with a modified radiole that acts as a plug, called an operculum.

Calcareous tube

Dive with diveshack

Where to Encounter in Malta

The following dive sites offer strong habitat match for Serpula vermicularis. All are accessible on a guided dive with diveshack.

5-30m
North Malta

Cirkewwa

Rocky reef with caves, arches and ledges hosting a rich diversity of reef species.

View dive site ›
5-50m
Gozo

Blue Hole

One of the Med's most famous reef dive sites. Rocky walls and archways covered in life.

View dive site ›
18-36m
South Malta

Um El Faroud

The wreck lies on a sandy bottom surrounded by rocky reef -- a diverse habitat attracting reef species.

View dive site ›
IUCN Red List Least Concern

Conservation Status

This species is assessed as Least Concern on the IUCN Red List. Mediterranean populations face ongoing pressure from fishing activity, habitat degradation, and climate-driven changes to prey availability.

Source: iNaturalist Guide #888
by Lesley Clements (CC BY-SA)
diveshack Mediterranean Marine Life guide