There are nearly 2,000 species of starfish (under phylum echinodermata) in the world’s oceans, making for a massive cast of characters that are distinctive in their own way. And contrary to popular belief, not all of them look like stars with five arms and bumpy bodies. In this article, we’ll highlight a few of the most interesting types of starfish that prove how truly diverse and beautiful marine life is.
Fascinating Starfish Species
In this article, you will see and learn about five types of starfish: the sunflower sea star, royal starfish, crown of thorns, paddle-spined seastar, and labidiaster annulatus. These species of starfish will surprise you not only with their distinct outward appearances, but also with their unique (and sometimes shocking) behaviors underwater.
Sunflower Sea Star
The sunflower starfish (more commonly known as the sunflower sea star) is one of the biggest starfish in the ocean. It can have as many as 24 arms around its robust body. The largest specimens are as many as 40 inches wide and they can weigh up to 11 pounds. Some are yellow like sunflowers while others are red, brown, or purple.
With their great size and flower-like appearance, they are a heavyweight contender for the most macho starfish with soft, velvet-textured bodies.
Characteristics and Features:
- Found in the Northeast Pacific
- Usually has 16 to 24 arms
- Can grow up to 3.3 feet in diameter
- Varies in color but usually yellow, purple, or brown
- Feeds on sea urchins, clams, snails, and the like
Royal Starfish
One of the most colorful types of starfish is the royal sea star. It is characterized by its vibrant central body with a deep purple color (which has ancient connections to royalty) and deep orange outline. And much like the common starfish (also known as the asterias rubens), it has five pointed arms that can grow up to 4 inches long.
The royal sea star mostly feeds on mollusks, particularly clams. It actually eats its prey whole, unlike many other species of starfish, and spits out the shell. Despite this rather gruesome fact, it reigns as one of the most attractive starfish in the ocean.
Characteristics and Features:
- Found in the Caribbean
- Has five flat arms
- Known for its deep purple and orange color
- Feeds mostly on clams
Crown of Thorns
The crown of thorns starfish is also robust but, as its name suggests, this type of starfish has an armament of poisonous spines all along its upper surface to keep itself safer from predators. Its spines radiate around its top surface, bringing about a resemblance to a crown of thorns. Fortunately, they only prey on coral reefs.
This species of large venomous starfish is common in Australia, but they can also be found in large areas between the Red Sea and the Indian Ocean, as well as across the Pacific Ocean until the western coast of Central America.
Characteristics and Features:
- Found in the Indo-Pacific subtropical waters
- Known for its venomous spines that form a crown-like shape
- Can have up to 21 arms
- Grows up to 9.8 to 13.8 inches in diameter
- Features a soft, membranous body
Paddle-Spined Seastar
This intricate-looking starfish with tiny tube feet is the smallest among all species of sea stars. While they look adorable up close, they can be difficult to spot on the sea floor as they only grow to be the size of a fingernail (5 millimeters or less than half an inch) upon reaching maturity. Their small, less-than-bite-sized nature is what keeps them safe from ravenous predators.
Its home is on the southern coast of Australia where it reproduces on its own by splitting itself in half, typically right down the middle, and growing out new arms. And when a problem occurs during reproduction, it can end up with only five arms instead of the usual six (such as in the photo above of the first ever photograph of the paddle-spined seastar).
Characteristics and Features:
- Found on the southern coast of Australia
- Grows up to 5 millimeters long
- Normally has 5 to 6 arms
- Covered with tiny tube feet
- Splits in half during reproduction
Labidiaster Annulatus
The labidiaster annulatus is much more opportunistic than most other large species of starfish as it catches and entangles its moving prey (usually krill, amphipods, younger starfish of the same species, and even brittle stars) with its long arms before feeding on it.
Compared to the other types of starfish on this list, the labidiaster annulatus grows the most number of arms (more than forty!) that can be as wide as 24 inches in diameter. It is also a cold-water starfish that lives at depths of 98 to 1,312 feet of Antarctic waters.
Characteristics and Features:
- Found in cold waters around Antarctica
- Typically has 40 to 45 flexible, slender arms
- Can grow up to two feet in diameter
- Uses its arms to capture its prey
