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Sea Cucumbers in the Family Holothuriidae

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One of the largest groups, members of the family Holothuriidae are the most common sea cucumbers found for sale as reef janitors. They typically have thick, muscular bodies equipped with tube feet used for clinging to the substrate and moving about, and pointed fleshy projections (papillae) often cover the body. With some species falling into the #1 feeding category, most are #2 type feeders, which makes these good sand sifting animals. Many cucumbers in this group may eject quantities of sticky filamentous threads (Cuvierian tubules) or expel their internal organs to defend themselves, and some can grow quite large.

Ashy (Holothuria cinerascens; Brandt, 1835) Sea Cucumber

Keoki Stender
  • Range: Indo-Pacific.
  • Size: To about 6 inches.
  • Characteristics: Filter feeder that extends its 20 branched tentacles to catch drifting food particles in the current.

Black Sea Cucumber (Holothuria atra)

Keoki Stender
  • Range: Indo-Pacific, Red Sea to Hawaii.
  • Size: To 24 inches.
  • Characteristics: Does not expel sticky threads, but will eject its internal organs. Commensal crab and Pearlfish host.

See Pictures of the Black Sea Cucumber (Holothuria atra)
  • Black-Spotted Sea Cucumber (Holothuria sp.)
  • Size: To about 12-15 inches.
  • Characteristics: Resembles the Indo-Pacific H. turriscelsa, but suggested it may be an undescribed cucumber endemic to Hawai'i, or a deep water form of the Stubborn Sea Cucumber (H. pervicax).

Difficult Sea Cucumber (Holothuria dificillis)

Keoki Stender
  • Range: Indo-Pacific.
  • Size: To about 5 inches.
  • Characteristics: Nocturnal. Eject hard to remove sticky threads so fine they resemble a milky fluid.

Impatient Sea Cucumber (Holothuria impatiens)

Photo by Keoki Stender
  • Range: Southern California, Hawai'i and other tropical waters.
  • Size: To 8 inches.
  • Characteristics: Expels fine sticky threads that may or may not be toxic.

Leopard Sea Cucumber (Holothuria pardalis)

Photo by Keoki Stender
  • Range: Indo-Pacific and Eastern Pacific.
  • Size: To about 4 inches.
  • Characteristics: Does not expel sticky threads.

Paradoxical Sea Cucumber (Bohadschia paradoxa)

Keoki Stender
  • Range: Indo-Pacific.
  • Size: To about 20 inches.
  • Characteristics: Expels sticky threads, reported to cause a rash or mild sting on humans. Commensal crab and Pearlfish host.

Edible or Burnt Hotdog Sea Cucumber (Holothuria edulis)

Keoki Stender
  • Range: Indo-Pacific, Red Sea to Hawai'i.
  • Size: To 12 inches.>
  • Characteristics: Have been reported to kill fish if injured or stressed.

Plump Sea Cucumber (Actinopyga obesa)

Photo by Keoki Stender
  • Range: Western and Central Pacific.
  • Size: To about 12 inches.
  • Characteristics: Does not expel sticky threads.

Sand Sea Cucumber (Holothuria arenicola)

Keoki Stender
  • Range: Indo-Pacific and tropical Western Atlantic.
  • Size: To about 10 inches.
  • Characteristics: Does not expel sticky threads.

Stubborn Sea Cucumber (Holothuria pervicax)

Photo by Keoki Stender
  • Range: Indo-Pacific.
  • Size: To about 12 inches.
  • Characteristics: Expels thick blue-white sticky threads.

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