Depth
Asterina · Echinoderms (Starfish, Urchins & Brittle Stars)

Cushion Star

Asterina gibbosa

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 Echinodermata
Genus Asterina
Species gibbosa

Echinoderm

Identification & Biology

  • IdentificationA small, pentagonal starfish with very short arms, giving it a puffy, cushion-like shape. The upper surface is grey-green to olive with darker patches. Sometimes orange or brown. The underside is pale yellow with a central mouth and rows of tube feet.
  • SizeDiameter up to 5 cm. A small and easy-to-overlook species.
  • Social HabitSolitary or in small groups. Found under rocks during the day. Can reproduce both sexually and by splitting in half (fission), with each half regenerating the missing portion.
  • HabitatRocky shores, tide pools, and shallow rocky reefs. Prefers sheltered areas under boulders and in crevices.
  • Depth0 to 10 m. Primarily an intertidal and very shallow subtidal species.
  • Feeds OnBiofilm, microalgae, detritus, and small encrusting organisms. An omnivorous grazer.
  • DistributionEastern Atlantic from Scandinavia to West Africa, and throughout the Mediterranean Sea. Common on Maltese rocky shores.
  • DescriptionAsterina gibbosa is one of the smallest and most inconspicuous starfish in Malta, easily found by turning over rocks in tide pools and shallow water (always replace them gently). Its ability to reproduce by splitting itself in two and regenerating the missing half is a remarkable feat of biology. Individuals produced by fission initially have uneven arm numbers.

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.

Cushion Star species card

Biology

Behaviour & Diet

Feeding Strategy

Omnivorous grazer that feeds on biofilm, encrusting organisms, and detritus on rocky surfaces. Everts its stomach over food items for external digestion.

Omnivorous grazer

Reproduction

Can reproduce both sexually through broadcast spawning and asexually by fission. Sexual reproduction peaks during warmer months, with planktonic larval development.

Broadcast spawner

Behaviour & Defence

Its rigid, heavily calcified body and low profile make it difficult for predators to grasp or overturn. Tube feet provide a powerful grip on rocky substrate.

Rigid body

Dive with diveshack

Where to Encounter in Malta

The following dive sites offer strong habitat match for Asterina gibbosa. 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