The red starfish at Rach Vem in Phu Quoc are horned sea stars, Protoreaster nodosus, also called chocolate chip sea stars after the dark knobbly spines on their backs. They grow up to about 30 cm across, are usually red, orange-brown or tan, and live on sheltered sand and seagrass in warm, shallow water in the western Pacific.
Many travellers call them red cushion starfish, but that name properly belongs to a Caribbean relative in the same family. At Rach Vem the starfish are easiest to see from November to April, early in the morning.
Horned sea stars in clear morning water
We reach Rach Vem before the group tours and take a private boat to the sandbar, where your guide shows you the starfish where they lie. Free cancellation up to 3 days before.
★Starfish Beach Private Morning TourRach Vem by private boat before the crowds, a swim at the starfish sandbar and seafood lunch over the water. · About 5.5 hoursSee the tour →North Phu Quoc Private Day: Starfish Beach to SunsetStarfish Beach by private boat, lunch on the water, Ganh Dau Cape, the Cua Can mangroves by kayak and a west-coast sunset. · About 10 hoursSee the tour →What species is the red starfish at Rach Vem?
The red starfish at Rach Vem are horned sea stars, Protoreaster nodosus, a species of the family Oreasteridae. The identification rests on their appearance, which matches the species closely, and on travel-guide sources that name it for Rach Vem; no published scientific survey of the starfish at Rach Vem was found.
A horned sea star is easy to recognise once you know what to look for. The table below lists the features you can check from above the water, without touching the starfish.
| Feature | What to look for |
|---|---|
| Shape | A fairly rigid five-armed star with tapering arms; four- or six-armed ones occur |
| Size | Up to about 30 cm across |
| Colour | Red or brown, sometimes light tan |
| Spines | A single row of dark, conical points along each arm, the “chocolate chips” |
| Underside | Tube feet in purple or pale, see-through pink |
| Where it sits | On sheltered sand, slightly muddy bottoms or among seagrass |
Colour varies from one starfish to the next at Rach Vem, so a pale, tan starfish next to a deep red one is usually the same species, not a different animal.
Is it a red cushion starfish?
Strictly, no. The name red cushion sea star belongs to Oreaster reticulatus, also called the West Indian sea star, which lives in shallow water in the western Atlantic and the Caribbean, from Florida and the Bahamas to the Gulf of Mexico. The starfish at Rach Vem are a different species on the other side of the world.
The mix-up is understandable. Both species belong to the same family, Oreasteridae, both are thick, stiff and often red, and both live on sand and seagrass in shallow water. In everyday travel writing, red cushion starfish has become a loose name for any large red sea star, and this site uses it the same way in its page title.
| Horned sea star | Red cushion sea star | |
|---|---|---|
| Scientific name | Protoreaster nodosus | Oreaster reticulatus |
| Other names | Chocolate chip sea star | West Indian sea star |
| Where it lives | Western Pacific, including Phu Quoc | Western Atlantic and Caribbean |
| Family | Oreasteridae | Oreasteridae |
| Size | Up to about 30 cm across | Up to about 50 cm across |
| Look | Rigid star with a row of dark conical spines on each arm | Broad cushioned disc, thick arms, blunt spines all over |
How do horned sea stars live?
Horned sea stars live on sheltered sandy or slightly muddy bottoms in warm, shallow water, often between the leaves of seagrass meadows or on open stretches of sand. They live in the intertidal zone and are occasionally left exposed on a very low tide, but they usually keep themselves under water.
Horned sea stars are opportunistic carnivores. Adults feed on most animals that stay fixed in one place, including hard corals and sponges, and they will hunt down snails; one was even recorded eating a sea urchin. They move on rows of small tube feet on the underside of the arms.
A horned sea star is also a small habitat of its own. Tiny shrimps of the genus Periclimenes, small brittle stars and even young filefish have been found living on their surface.
Why horned sea stars need care
Horned sea stars do not cope well with rapid change, and like all starfish they breathe through thin gills on the skin and through their tube feet, which work only in water. Out of the water they can die within minutes. Overharvesting for the shell trade, the aquarium trade and dried curios has a severe impact on the species where it is collected.
How to see them without harm is covered in our guide on seeing the starfish without harming them, and the best months and hours are in our guide to the best time to see starfish.
Where do horned sea stars live besides Phu Quoc?
Horned sea stars live in warm, shallow water across the western Pacific. The species was long described as widespread in the Indo-Pacific, but more recent research suggests it is restricted to the western Pacific, from Thailand to Samoa and from Japan to New Caledonia. Phu Quoc, in the Gulf of Thailand, sits near the western edge of that range.
Wherever they occur, horned sea stars need the same conditions: sheltered water, a soft bottom of sand or seagrass, and shallows that stay calm. Rach Vem offers all three in the dry season, from November to April, when its starfish are easiest to see. From May to October, when the southwest monsoon stirs up the north coast, they are much harder to see.
The whole visit, from the road north to the boat and the raft-house lunch, is covered in our Rach Vem beach guide.
If you would like to see them up close
A private boat to the clear water at the sandbar, early in the morning, with a guide who knows the rule.
Starfish Beach Private Morning TourAbout 5.5 hoursSee the tour →North Phu Quoc Private Day: Starfish Beach to SunsetAbout 10 hoursSee the tour →Red starfish in Phu Quoc: common questions
What kind of starfish are at Starfish Beach in Phu Quoc?
The starfish at Rach Vem Starfish Beach in Phu Quoc are horned sea stars, Protoreaster nodosus, also called chocolate chip sea stars. They are red, brown or tan with a row of dark spines along each arm.
Why are the starfish in Phu Quoc red?
Horned sea stars are naturally red, brown or light tan, and the colour varies between individuals. The red ones stand out most against the pale sand and green seagrass at Rach Vem.
How big are the starfish at Rach Vem?
The horned sea stars at Rach Vem grow up to about 30 cm across, roughly the width of a dinner plate. Smaller and larger ones share the same sandbar.
Are red cushion starfish found in Vietnam?
Not in the strict sense. The red cushion sea star, Oreaster reticulatus, lives in the western Atlantic and Caribbean. The red starfish in Phu Quoc are horned sea stars, a relative in the same family.
Where else do horned sea stars live?
Horned sea stars live in warm, shallow water in the western Pacific, from Thailand to Samoa and from Japan to New Caledonia, according to recent research. Phu Quoc lies inside that range.
The red starfish of Rach Vem, left where they are
We collect you at your hotel, reach the sandbar in the clear morning hours and carry on by private boat to Ham Rong Cape. Every boat ride and lunch is included.
★Starfish Beach Private Morning TourRach Vem by private boat before the crowds, a swim at the starfish sandbar and seafood lunch over the water. · About 5.5 hoursfrom$63/ person›
Choose your group size · price is the group totalSolo traveller$175BOOK →2 guests$200BOOK →3 guests$225BOOK →4 guests$250BOOK →See the full tour page →North Phu Quoc Private Day: Starfish Beach to SunsetStarfish Beach by private boat, lunch on the water, Ganh Dau Cape, the Cua Can mangroves by kayak and a west-coast sunset. · About 10 hoursfrom$91/ person›
Choose your group size · price is the group totalSolo traveller$255BOOK →2 guests$295BOOK →3 guests$330BOOK →4 guests$365BOOK →See the full tour page →Species information and starfish season as of September 2026.