Two-Spined Sea Starfish
(Astropecten duplicatus)

Description

The Two-Spined Sea Star (*Astropecten duplicatus*) is a fascinating marine invertebrate. I have gathered the following information from the search results:

**Scientific Name:** *Astropecten duplicatus*
**Common Name / Variant:** Two-Spined Sea Star, Two-spined starfish
**Maximum Size:** Grows to about 20 cm (8 in) in diameter. Some sources state 10-30 cm. I’ll use 20cm as a common maximum.
**Origin:** Native to the eastern Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. Its range extends from Cape Hatteras, Florida, Cuba, and the Bahamas to Mexico, Colombia, Venezuela, and Guyana. Also mentioned: Western Atlantic Ocean, Belize and Bonaire, Florida Keys, Bahamas, Caribbean, Brazil. Some sources incorrectly include the Mediterranean and Indo-Pacific, which conflicts with other detailed descriptions of *A. duplicatus* specifically. I will stick to the primary range.
**Appearance & Behaviour:** Normally has five long, slender, tapering arms. The upper surface is pale grey or reddish-brown and the lower surface is pale brown or orange. It has two prominent spines on the marginal plates, though these can be worn away. It spends the day semi-immersed in sediment on the seabed. It is a carnivore and hunts at night for bivalve molluscs and gastropods, which it swallows whole and later regurgitates undigested fragments. It’s a predator that feeds on a variety of prey, including bivalves, gastropods, and polychaete worms. It uses its stomach to digest prey outside its body before absorbing nutrients. Primarily a sand-sifting species.
**Care Level:** While some related species like *Astropecten polycanthus* (Sand Sifting Sea Star) are described as “Easy” and “Peaceful”, and some general starfish advice suggests they starve in tanks, the *Astropecten duplicatus* specifically feeds on bivalves, gastropods, and polychaete worms. This suggests it requires a mature sand bed with a thriving microfauna. It is a predator of small invertebrates. This implies it’s *not* generally reef safe if you have clams or snails you want to keep. Some general advice for starfish emphasizes intolerance to sudden changes in oxygen, salinity, and pH, and copper-based medications. Drip acclimation is recommended. Its predatory nature on bivalves and gastropods means it’s not reef safe for tanks with desirable mollusks. Given its specific diet, it’s not “easy” for a typical community tank. I’ll lean towards moderate/advanced for its specific dietary needs. It is described as eating small invertebrates including shrimp, urchins, mollusks, bivalves, or other small sea stars (this was for *Astropecten polycanthus*, but the predatory nature on bivalves is consistent for *A. duplicatus*).

**Tank Essentials:** Needs a large tank with a deep, mature sand bed. Found on sand or other soft sediments and in seagrass meadows. Depths down to about 500 meters (1,600 ft) in the wild, but typically shallow waters, intertidal to 200 meters. Minimum tank size depends on its max size (20cm) and its need for a large sand bed. A common recommendation for larger starfish is 150L (40 gallons) or more, with a deep sand bed. For a 20cm star, 150-200L seems reasonable.
**Water Parameters:** For marine invertebrates, general marine parameters apply. pH 8.1-8.4, dKH 8-12, sg 1.023-1.025, Temperature 22-26°C (72-78°F) are common for tropical marine setups. I’ll use 22-26°C and pH 8.1-8.4. Salinity around 1.025.
**Lifespan:** Data unavailable specifically for *Astropecten duplicatus*. Some general sea star lifespans are 2-3 years or more. I’ll mark as “[data unavailable]”.
**Swimming Zone:** Bottom (substrate-dwelling), semi-immersed in sediment.

**Refinement:**
* **Headline**: Needs to be catchy and include common name.
* **Overview**: Appearance and behavior, especially its sand-dwelling and predatory nature.
* **Care Level**: Difficulty (moderate to advanced due to diet), temperament (peaceful towards fish, but predatory on invertebrates), compatibility (not reef safe with certain inverts).
* **Tank Essentials**: Min tank size, deep sand bed, marine parameters.
* **Diet**: Carnivore, target feeders, bivalves, gastropods, worms.
* **Why Buy From Us**: Standard store advantages.
* **List**: Fill in details.
* **Call-to-action**: Imperative, concise.

Let’s check the SEO keywords: “buy Two-Spined Sea Starfish online”, “Two-Spined Sea Star care”, “healthy aquarium fish” (even though it’s an invertebrate, it’s about the general aquarium).

Double-check accuracy and ethics:
* Temperature, pH, size: Plausible and consistent with marine life.
* Conflicting sources: Prioritize specific *A. duplicatus* info, or common marine parameters where specific data is absent. The reef-safe status is critical; *A. duplicatus* is a predator of mollusks, so it is *not* reef safe for keeping clams/snails. This differs from some “sand sifting starfish” general statements which might be for other *Astropecten* species. I will emphasize its predatory nature.
* No dubious claims.
* Promote responsible fishkeeping: Emphasize tank size, deep sand bed, and specific diet needs.

Drafting content:
* **Headline**: Two-Spined Sea Star: A Unique Substrate Dweller for Your Marine Tank
* **Teaser**: Add this fascinating *Astropecten duplicatus* to your dedicated marine aquarium. Known for its sand-sifting habits and striking appearance, it brings natural activity to your substrate.
* **Overview**: The Two-Spined Sea Star (*Astropecten duplicatus*) typically displays a pale grey to reddish-brown upper surface and a pale brown or orange underside, with five tapering arms radiating from a central disc. Its common name comes from the two prominent, albeit often worn, spines on its marginal plates. This species spends its days partially buried in the sand, emerging at night to hunt. It is a captivating addition, actively sifting through your substrate.
* **Care Level**: Moderate to advanced. While peaceful with fish, the Two-Spined Sea Star is a nocturnal predator of small invertebrates, including bivalves and gastropods. It is generally not considered reef-safe for tanks housing desirable mollusks. Ensure a well-established system for its specialized diet, providing a stable environment for this unique bottom dweller.
* **Tank Essentials**: A minimum of 150 litres is recommended, featuring a deep sand bed (at least 7-10 cm) for burrowing and foraging. Maintain stable marine water parameters: Specific Gravity 1.023-1.025, pH 8.1-8.4, and Temperature 22-26°C. Provide ample live rock for additional surface area and microfauna development.
* **Diet**: As a carnivorous scavenger, *Astropecten duplicatus* primarily preys on small bivalves, gastropods, and polychaete worms found within the sand bed. Supplement its diet with meaty foods like chopped clam, shrimp, or squid if natural food sources become depleted.
* **Why Buy From Us**: When you buy Two-Spined Sea Starfish online from us, you receive healthy, responsibly sourced marine invertebrates. We prioritize ethical handling and humane shipping, ensuring your new additions arrive in prime condition, ready to thrive in your healthy aquarium fish and invertebrate setup.
* **List**:
* Scientific Name: Astropecten duplicatus
* Common Name / Variant: Two-Spined Sea Star
* Maximum Size: 20 cm
* Origin: Eastern Atlantic Ocean, Caribbean Sea, Gulf of Mexico
* pH Range: 8.1–8.4
* Temperature: 22–26°C
* Lifespan: [data unavailable]
* Swimming Zone: Bottom
* **Call-to-action**: Add this fascinating sand-sifting star to your aquarium today!

This looks good and covers all requirements.

Two-Spined Sea Star: A Unique Substrate Dweller

Add this fascinating Astropecten duplicatus to your dedicated marine aquarium. Known for its sand-sifting habits and striking appearance, it brings natural activity to your substrate.

Overview

The Two-Spined Sea Star (*Astropecten duplicatus*) typically displays a pale grey to reddish-brown upper surface and a pale brown or orange underside, with five tapering arms radiating from a central disc. Its common name comes from the two prominent, albeit often worn, spines on its marginal plates. This species spends its days partially buried in the sand, emerging at night to hunt. It is a captivating addition, actively sifting through your substrate.

Care Level

Moderate to advanced. While peaceful with fish, the Two-Spined Sea Star is a nocturnal predator of small invertebrates, including bivalves and gastropods. It is generally not considered reef-safe for tanks housing desirable mollusks. Ensure a well-established system for its specialized diet, providing a stable environment for this unique bottom dweller.

Tank Essentials

A minimum of 150 litres is recommended, featuring a deep sand bed (at least 7-10 cm) for burrowing and foraging. Maintain stable marine water parameters: Specific Gravity 1.023-1.025, pH 8.1-8.4, and Temperature 22-26°C. Provide ample live rock for additional surface area and microfauna development.

Diet

As a carnivorous scavenger, *Astropecten duplicatus* primarily preys on small bivalves, gastropods, and polychaete worms found within the sand bed. Supplement its diet with meaty foods like chopped clam, shrimp, or squid if natural food sources become depleted.

Why Buy From Us

When you buy Two-Spined Sea Starfish online from us, you receive healthy, responsibly sourced marine invertebrates. We prioritize ethical handling and humane shipping, ensuring your new additions arrive in prime condition, ready to thrive in your healthy aquarium fish and invertebrate setup.

• Scientific Name: Astropecten duplicatus
• Common Name / Variant: Two-Spined Sea Star
• Maximum Size: 20 cm
• Origin: Eastern Atlantic Ocean, Caribbean Sea, Gulf of Mexico
• pH Range: 8.1–8.4
• Temperature: 22–26°C
• Lifespan: [data unavailable]
• Swimming Zone: Bottom

Add this fascinating sand-sifting star to your aquarium today!