American Oceans

Biggest Starfish Ever Recorded

Starfish come in many species. While some can have up to 50 arms, others typically have the standard five rays that they are born with.

largest starfish spikey arms feed on algae underwater

Some feed on algae and remain omnivores, and others act as voracious feeders. Find out all these differences and more by learning about the ten largest starfish recorded.

Midgardia Xandaros

The Midgardia Xandaros holds the record for the largest starfish in the world. It measures a whopping 53 inches in diameter. What’s more, the Midgardia xandaros has 12 arms compared to the usual five.

These arms are covered in spines, which help them to move around. Despite their body span measuring only an inch, each of their arms spans two feet long. Not many marine biologists or diving hobbyists have ever seen this species of starfish.

It lives 2,000 feet deep in the waters of the Gulf of Mexico. Hence, marine biologists have not collected too much information about the Midgardia xandaros, leaving the species relatively unknown.

Colors are usually bright, which scares off their predators to keep them safe in the marine wilds. Their distinctive colors may also act as camouflage, giving them a layer of protection from nearby predators.

Sunflower Sea Star

The Sunflower Sea Star is the second biggest starfish recorded, measuring 39 inches in diameter.

sunflower sea star kelp forest habitat

While their diameter is smaller than the Midgardia Xandaros species, some of them can have as many as 24 arms.

Their habitat is the kelp forest. Typical food sources are clams, sea urchins, snails, crabs, and squid. These are usually almost or already dead.

The king crab is the usual predator of the Sunflower Sea Star. As with many starfish, the Sunflower Sea Star doesn’t need to worry about losing an arm while escaping from the king crab’s snapping claws. It often takes only weeks for an individual to restore a lost arm.

endangered sunflower sea star species

Unfortunately, this Sunflower Sea Star has become an endangered species because of a sea star wasting syndrome that has affected the Pacific Ocean for the last ten years.

Pink Sea Star

Pisaster brevispinus is the scientific name for the Pink Sea Star. This is the third-largest starfish recorded. Certain ones can range in size between 20-28 inches in diameter.

pink sea star pisaster brevispinus pacific coast mud

The species has populations throughout North America. However, the predominant habitat is the mud and sand of the Pacific Coast.

You can find the Pink Sea Star from Alaska to the southern regions of California. Colors range from a pink shade to a lavender hue. The hues are dependent upon where they live along the Pacific Coast and their habitat’s conditions.

Their diet includes bivalve mollusks, clams, mussels, polychaetes, and sand dollars. The Pink Sea Star is a scavenging species that prefer to eat dead prey.

scavenging pink sea star species hunt their prey

You will rarely see them hunt and kill prey like other starfish. However, they will hunt their prey, if necessary.

The Pink Sea Star lives in ocean depths as deep as 360 feet. That is only close to a fifth of the depth that the Midgardia Xandaros dwells (2,000 feet deep).

Thankfully, they are not a critically endangered species like the Sunflower Sea Star. The Pink Sea Star is still a threatened species.

Spiny Starfish

Some Spiny Starfish is a light gray-green in color with a purple tip on each of its five arms. Reflecting its name, this species has a spiny appearance with three spine rows along its arms.

spiny starfish with light gray-green color

As a voracious predator, the Spiny Starfish is known to feed on other starfish, crabs and other crustaceans, and bivalve mollusks.

Dwelling down in the Atlantic Ocean at 650 feet in depth, their desired habitat is usually muddy and rocky.

Some average in size at 12 inches, while others can reach as large as 28 inches in diameter. Spiny Starfish have also been found on the southwest and western coasts of Wales and England.

spiny starfish sea stars in their habitat

If the species becomes stressed, for whatever reason, they may shed an arm or two to feel more at ease.

Stress could happen from being pursued by a predator or another condition in their habitat. Most Spiny Sea Stars in the wild have three or four arms attached to their bodies. One or more of their arms might be in the process of regrowing on their bodies.

Giant Sea Star

Pisaster giganteus is the scientific name for the Giant Sea Star. They have gone by other designations, including the Giant-spined Starfish.

Measuring 24 inches in diameter, the Giant Sea Star likes to live in rocky areas, usually in shallow water.

They may be attached directly to the ocean floor, on a rock, or even on pier supports if they are more adventurous.

Otherwise, they live almost 290 feet down into the water. That is a more shallow dwelling than other starfish species. That would explain why they do not mind sitting on pier supports once in a while.

It lives on the western coasts of North America, ranging from Southern California to British Columbia. Typical predators are seabirds and sea otters.

The Giant Sea Star likes to eat mollusks, vermetid gastropods, barnacles, bivalves, limpets, and snails. The species comes in many colors, including brown, orange, dark blue-gray, and pink.

Antarctic Sun Starfish

The Antarctic Sun Starfish is known by the scientific name of Labidiaster annulatus. With even more arms than the Sunflower Sea Star in this lineup, the Antarctic Sun Starfish can have as few as 40 arms to as many as 50.

When they are born, the Antarctic Sun Starfish starts with five rays on its body. As they grow, they add more rays to their bodies. An Antarctic Sun Starfish has the potential to achieve a maximum of 50 arms.

They measure about 23 inches in diameter. Some members have been reported at depths as deep as 1,800 feet in the ocean.

Known as coldwater starfish, they predominantly eat amphipods and krill. The Antarctic Sun Starfish is adaptable when it hunts.

It can scavenge for dead fish to eat or chase its prey on the ocean floor like other starfish. The Antarctic Sun Starfish can grab their prey while they are swimming in the ocean column for them to feast on.

Mottled Star

The Mottled Star, or the Evasterias troschelii per its scientific name, is found on the northwestern coast of North America.

This species is prevalent in the Kamchatka Peninsula located near eastern Russia. Mottle Stars can often be observed sitting on a rock at about 230 feet in the Bichevskaya Bay.

Another name for this species is the False Ochre Star. They come in many colors (including brown, orange, dark blue-gray, and pink) and measure as much as 22 inches in diameter. A Mottle Star is born with five rays and should keep the same amount through their lifespan.

This species gets its name from the mottled appearance on its body and two of its feet are powerful enough to break open a mollusk shell to feast on the animal inside for lunchtime.

Red Cushion Sea Star

The West Indian Sea Star’s scientific name is Oreaster reticulatus. It has populations in the Caribbean Sea and the western coasts of the Atlantic Ocean.

red cushion sea star oreaster reticulatus underwater

This sea star prefers more shallow waters, only going as much as 120 feet deep into the water. Hence, the Red Cushion Sea Star is one of the largest starfish recorded that would be easier to see if you took a quick dive into the Caribbean Sea.

The fascinating mating pattern of the Red Cushion Sea Star is called broadcast spawning. That involves females releasing their eggs at the same time that the males release their sperm. The eggs and sperm join together to fertilize the babies.

While most of these species have five rays on their body, others have been observed to have more. Intriguingly, Red Cushion Sea Star is an omnivore and they eat sponges, smaller invertebrates, and algae.

Stimpson’s Sun Star

The Stimpson’s Sun Star is also known by the scientific name, Solaster stimpsoni. It measures 20 inches in diameter and usually has up to 12 arms.

stimpson’s sun star solaster stimpsoni with 12 arms

Other designations include Striped Sunstars. The starfish measures 20 inches in diameter and usually has 12 arms. In the wild, that can sometimes be as few as nine.

It’s the ninth-largest starfish recorded worldwide. Some have been measured as small as ten inches in diameter. 

Certain Stimpson’s Sun Star species are orange or red. Each of them has blue or purplish-gray stripes underneath their rays, starting from the central disk of their bodies.

stimpson’s sun star with purplish-gray stripes underneath rays

While most examples of this starfish prefer rocky territories, some have been found in sandy and muddy habitats, too. The Morning Sunstar is one of the predators of Stimpson’s Sun Star.

This species feasts on brachiopods, sea pens, sea cucumbers, and ascidians. They can be found in water depths as much as 656 feet.

Northern Pacific Sea Star

The Northern Pacific Sea Star is scientifically known as Asterias amurensis. It has also been called the Japanese common starfish.

northern pacific sea star asterias amurensis throughout waters

It can be found throughout the waters of Alaska, China, Japan, Korea, and the far eastern waters of Russia.

If you go to British Columbia or the Aleutian Islands, you could spot a Northern Pacific Sea Star there, too.

Most are yellow with a purplish hue splattered throughout them. Its diameter measures 19 inches. The native bivalves have greatly decreased in the marine habitat of New Zealand and Australia thanks to Norther Pacific Sea Stars.

northern pacific sea star in marine habitat

It’s a voracious starfish that eats scallops, clams, and mussels, pretty much any dead fish that it can get its hands on to live and thrive in the ocean.

FAQs About Starfish

Now that you have learned about the ten largest recorded starfish, you may still have some questions about these remarkable creatures. Here are some answers to frequently asked questions about starfish.

How many species of starfish are there throughout the world?

There are more than 2,000 species of starfish worldwide according to the Pacific Beach Coalition. While many of these are harmless, some are venomous!

Are starfish fish?

While they are called “starfish,” they are considered echinoderms. These are invertebrates that do not have any backbones, tails, or fins.

What keeps a starfish alive?

Starfish do not have a brain in their body, nor do they filter blood throughout their system. Instead, saltwater goes through their system to keep them alive and thriving.

How long can starfish survive in the wild?

A starfish can survive in the wild for up to 35 years.

How long do starfish survive in captivity?

Typically, most starfish in captivity survive for only five to ten years at most.

How do starfish eat if they do not have a mouth?

Starfish have two stomachs in which food is digested: the pyloric stomach and the cardiac stomach. The cardiac stomach grabs hold of the starfish’s prey and starts the digestion process once the prey is consumed.

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