Depth
Reteporella · Bryozoans (Moss Animals)

Neptune's Lace

Reteporella grimaldii

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 Bryozoa
Genus Reteporella
Species grimaldii

Bryozoan

Identification & Biology

  • IdentificationA bryozoan colony that forms large, flat, fan-shaped or lace-like sheets with a distinctive mesh pattern of tiny holes. Pale orange to cream. The perforated sheet structure is unique and unmistakable.
  • SizeColony diameter up to 20 cm or more. The flat sheets are thin and delicate.
  • Social HabitColonial. Grows in flat, fan-shaped sheets on rocky walls, oriented into the current. Very fragile when dry.
  • HabitatRocky walls, overhangs, and cave entrances with good current flow. Requires hard substrate.
  • Depth15 to 200 m. Most common on deeper, current-swept walls.
  • Feeds OnPlankton, bacteria, and suspended organic particles filtered from the water.
  • DistributionMediterranean Sea and adjacent eastern Atlantic. Present in Maltese waters on deeper reefs.
  • DescriptionReteporella grimaldii is one of the most beautiful and structurally impressive bryozoans in the Mediterranean. Its flat, perforated sheets look like delicate lacework and are oriented across the current to maximise food capture. The colonies are extremely fragile and must never be touched. They are a signature feature of deeper Mediterranean walls and caves.

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.

Neptune's Lace species card

Biology

Behaviour & Diet

Feeding Strategy

A delicate, lace-like bryozoan that filter-feeds using lophophores extended by each zooid to trap phytoplankton, bacteria and fine organic particles from the surrounding water.

Filter feeder

Reproduction

Broods larvae in ovicells on the colony surface. Released larvae are lecithotrophic, settling quickly on nearby hard substrate. Asexual budding expands the fenestrate colony outward.

Brooding

Behaviour & Defence

The fenestrate (window-like) growth form allows water to pass through, reducing drag and mechanical stress from currents. Lightly calcified zooids provide some protection from soft-bodied predators.

Flexible form

Dive with diveshack

Where to Encounter in Malta

The following dive sites offer strong habitat match for Reteporella grimaldii. 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