Difference Between Sea Star and Starfish

The main difference between sea star and starfish is that the sea star or star of the sea is a common name for starfish in many European languages whereas starfish are asteroids, star-shaped echinoderms. Moreover, starfish are invertebrates that live exclusively marine habitats. They typically have a central disk and five arms.

Key Areas Covered

1. Sea Star
     – Definition, Significance
2. Starfish
     – Definition, Characteristics, Behavior
3. What are the Similarities Between Sea Star and Starfish
     – Outline of Common Features
4. What is the Difference Between Sea Star and Starfish
     – Comparison of Key Differences

Key Terms

Asteroids, Echinoderms, Invertebrates, Sea Star, Starfish

Sea Star – Definition, Significance

Sea stars are not actual fish, but they are echinoderms, closely related to sea urchins and sea cucumbers. Therefore, in several European languages including French, Dutch, German, Spanish, and Swedish, these animals are called sea stars or stars of the sea. Sea star can be considered as the name that is more appropriate for asteroids due to their relatedness to ‘true fish’.  

Figure 1: Sea Star (Fromia monilis)

Starfish – Definition, Characteristics, Behavior

Starfish is a common name used in many parts of the world to describe animals in the class Asteroidea. Starfish are marine invertebrates as they belong to the phylum Echinodermata. More than 2,000 species of starfish live in oceans. In general, starfish have a central disk and five arms, which are radial. The undersides of the arms bear tube feet, which help mainly in locomotion. In predatory species, tube feet are useful for opening the shells of mollusks. Some starfish species may have more than five arms. Both upper and aboral surfaces of starfish can be spiny, granular or smooth. Many species of starfish are brightly-colored with various shades of red, orange, blue, brown or gray.

Figure 2: Sunflower Sea Star (Pycnopodia helianthoides)

Most starfish are carnivores. They can grow up to 5-10 inches, and weigh up to 11 lbs. Starfish can live up to 35 years. They can regenerate limbs or even the whole body.

Similarities Between Sea Star and Starfish

• Sea star and starfish are two common names used for the asteroids, the star-shaped echinoderms exclusively live in marine habitats.

Difference Between Sea Star and Starfish

Definition

Sea star is a common name used in several European languages for describing starfish while starfish refers to a marine echinoderm (invertebrate) with five or more radiating arms.

Used in

The name sea star is used in several European languages including French, Dutch, German, Spanish, and Swedish while starfish is the name used in other parts of the world.

Appropriacy

While sea star is the appropriate, common name for asteroids, starfish is less appropriate since asteroids are not real fish.

Conclusion

Sea star is the common name for asteroids used in many European languages while starfish is the common name for these animals used in other parts of the world. Since starfish is not a real fish, sea star or the star of the sea can be the most appropriate name for this type of animals. Therefore, the main difference between sea star and starfish is the parts of the world where these names are used and the appropriacy of the names.

Reference:

1. “Starfish (Sea Stars).” National Geographic, 15 June 2017, Available Here

Image Courtesy:

1. “Fromia monilis (Seastar)” By Nhobgood Nick Hobgood – Ain wirk (CC BY-SA 3.0) via Commons Wikimedia  
2. “Sunflower Sea Star (Pycnopodia helianthoides)” By Sam Wilson – originally posted to Flickr as Sunflower Sea Star (Pycnopodia helianthoides) (CC BY-SA 2.0) via Commons Wikimedia