Depth
Protula · Worms & Tube Worms

Red-spotted Horseshoe

Protula tubularia

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 Protula
Species tubularia

Polychaete

Identification & Biology

  • IdentificationA tube worm that builds a hard, white, calcareous tube cemented to rock surfaces. The worm extends a crown of bright red to orange feathery tentacles (radioles) tipped with a distinctive horseshoe-shaped operculum (plug) used to seal the tube when retracted.
  • SizeTube length up to 5 cm. Fan diameter up to 3 cm.
  • Social HabitSolitary. Found on hard substrates, often in shaded positions. The hard calcareous tube is a permanent structure that remains on the rock long after the worm dies.
  • HabitatRocky walls, cave ceilings, and overhangs. Attaches to any hard surface.
  • Depth2 to 60 m. Common throughout its depth range.
  • Feeds OnPlankton and suspended organic particles captured by the feathery radioles.
  • DistributionEastern Atlantic and throughout the Mediterranean Sea. Common in Maltese waters.
  • DescriptionProtula tubularia is a small but colourful tube worm that brightens up rocky walls and cave ceilings. Its bright red fan is easy to spot, and the hard white tube remains visible even when the worm is retracted. Empty tubes of this species (and the related Serpula) are a common feature of Mediterranean rock surfaces, sometimes accumulating in dense crusts.

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-spotted Horseshoe species card

Biology

Behaviour & Diet

Behaviour & Defence

Releases ink as a confusion cloud when threatened, providing precious seconds to escape predators.

Defensive

Dive with diveshack

Where to Encounter in Malta

The following dive sites offer strong habitat match for Protula tubularia. 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.

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5-50m
Gozo

Blue Hole

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

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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