Common name: arctic cushion star

Scientific name: Hippasteria phrygiana (Parelius, 1768)
A close-up picture of a Horse star, Hippasteria phrygiana is a species of sea star, aka starfish, belonging to the family Goniasteridae. Picture from the Weather Islands, Skagerrak Sea, SwedenA close-up picture of a Horse star, Hippasteria phrygiana is a species of sea star, aka starfish, belonging to the family Goniasteridae. Picture from the Weather Islands, Skagerrak Sea, Sweden

General information

The Hippasteria Sea Star, or Phrygian Sea Star, is a deep-sea starfish species known for its distinctive appearance and preference for cold-water habitats. Unlike many other starfish, Hippasteria phrygiana is not commonly found in shallow reef environments, making it a rare and intriguing addition to specialized cold-water marine aquariums.

Details

Recommended minimum tank volume
100 liter (26 gallons)
Salinity
S.G. 1.023 to 1.025
Temperature
22 to 26 °C (72 to 79 °F)
Acidity
pH 8.1 to 8.4
Average size
30 cm (1′)
Care level
Moderate to easy
Diet
Carnivore
Reefsafe
Yes
Aggression
Peaceful
Captive bred
No

Taxonomy

  1. Kingdom
    Animals
    Animalia
  2. Phylum
    Echinoderms
    Echinodermata
  3. Class
    Starfish
    Asteroidea
  4. Order
    Starfish
    Valvatida
  5. Family
    Sea Stars
    Goniasteridae
  6. Genus
    Hippasteria Sea Stars
    Hippasteria
  7. Species
    arctic cushion star
    Hippasteria phrygiana (Parelius, 1768)
  8. Synonyms
    Asterias equestris Linnaeus, 1758
    Asterias equestris de Lamarck, 1816
    Asterias johnstoni Gray in Johnston, 1836
    Asterias phrygiana Parelius, 1768
    Astrogonium aculeatum Barrett, 1857
    Astrogonium phrygianum (Parelius, 1768)
    Goniaster abbensis Gray, 1843
    Goniaster equestris (Linnaeus, 1758)
    Goniaster phrygianus (Parelius, 1768)
    Hippasteria aleutica Clark & Jewett, 2011
    Hippasteria argentinensis Bernasconi, 1961
    Hippasteria colossa Djakonov, 1950
    Hippasteria cornuta Gray, 1840
    Hippasteria derjungini Djakonov, 1950
    Hippasteria europaea Gray, 1840
    Hippasteria hyadesi Perrier, 1891
    Hippasteria insignis Dons, 1938
    Hippasteria johnstoni (Gray, 1836)
    Hippasteria kurilensis Fisher, 1911
    Hippasteria leiopelta armata Fisher, 1911

Care

Caring for Hippasteria Sea Stars requires a well-maintained system that can replicate their natural deep-sea environment. This includes stable, low temperatures and low light conditions. They are sensitive to changes in water quality, so excellent filtration and regular water testing are crucial. Their diet consists mainly of small invertebrates and detritus, so providing a variety of appropriate foods is essential for their health.

Reproduction

Reproduction in Hippasteria Sea Stars is not well-documented in home aquariums due to their rarity and specific requirements. In the wild, they reproduce by releasing gametes into the water column, where fertilization occurs externally. Captive breeding is challenging and not commonly reported among hobbyists.

Habitat

Hippasteria phrygiana is typically found at depths ranging from 200 to 600 meters, where the water is cold and the light is dim. They inhabit areas with soft substrates, such as mud or fine sand, which provide a habitat for the small invertebrates they feed on. In the aquarium, simulating this environment is key to their well-being.