Although we know them as starfish, they are not technically a fish. Marine Biologists actually want to rename them sea stars, and the name is catching on… slowly.
They are star-shaped aquatic creatures, and for the most part, we find them rather sweet and beautiful.
They are classified as being part of the Phylum Echinodermata, and are classed as Asteroidea. This is the largest class of the above Phylum classification.
They are typically carnivorous animals, some may be scavengers. However, there are some species of starfish (or sea star) that are omnivorous.
They tend to feed on very slow moving sea organisms, typically feasting on barnacles, gastropods, polychaetes, or bivalves. Some might feed on fish, plankton and so on.
Typically, their diet will also be subjective to their size, as they can vary in size quite significantly.
Today, we will discuss with you the typical diet of a starfish, and talk you through the many variations of starfish and their relative diets! Time to feast!
Understanding Basic Starfish Diet
Starfish diets vary depending on the type of starfish. Some will eat sponges, bacteria, others may eat sea cucumbers, sea urchins, or fish eggs.
Larger starfish might eat fish, clams, mussels, sea urchins, and others may go for algae, snails, and sponges.
It varies. You may have seen video footage of a large starfish that travels around the ocean floor decimating everything in its path, we won’t tell you which type this is just yet though.
But it can vary, smaller starfish might stick to sponges and bacteria, but a larger starfish can eat whole fish and clams!
Types Of Starfish & Their Diets
There are 4 main types of starfish that exist. We will talk you through each of these and their typical diet.
Now is the time to start guessing which starfish is the one we mentioned above. If you get it right then you deserve a gold star!
The Pacific Blood Starfish
The Pacific Blood Starfish will typically eat bacteria, plankton, and sponges.
These starfish are quite small, usually between 10-12 cm in size, and are typically found off the Pacific coast of North America.
They are often named the ‘blood star’ because they are usually a beautiful vibrant red color. They can also be a reddish-orange color.
They are best known for their long and slender arms, having 5 of them, you can find them in coastal waters around rocks.
Their diet is varied with 3 main sources of sustenance, but it often eats smaller things.
The Leather Starfish
The Leather Sea star will typically eat anemones. However, it has also been known to eat sponges, hydroids, sea pens, sea urchins, sea cucumbers, and even fish eggs.
This type of starfish is a bit bigger than the former, they can be up to 30 cm in size.
You can tell that a starfish is a leather starfish due to it having a leathery and mottled surface. It will usually be yellow or gray in appearance.
However, you can often find them with red, purpose, yellow, or brown patches on them.
Their arms are short and broad in comparison to many sea stars, you could say it looks a bit chubby in comparison to the blood starfish.
They are often found in the Pacific waters of North America, and can often be found at depths beyond 90 meters, so it’s unlikely that you will just find them hanging out at the beach.
The Sunflower Starfish
Here is the one you are looking for! This is the starfish that sweeps the seafloor in those videos you’ve seen!
The Sunflower Starfish eats sea cucumbers, sand dollars, crustaceans, sea urchins, fish, and clams, as well as gastropods.
This starfish is the largest of all types of sea star, it also has the most arms and weighs a lot more. In fact, they have a maximum arm span of 1 meter!
They can also have anywhere between 16 and 18 arms!
In spite of their sheer size their main predators are King Crab and… other sea stars. Sunflower Sea Stars may even eat each other, although it is rare as there is much easier food hanging about.
Sea Stars are the starfish you see in those videos that sweep the ocean floor and leave a trail of corpses in its wake.
They are actually extremely important as well, as they are the predators of sea urchins, which are well known for destroying kelp forests which are the habitats for many marine animals, and help to maintain the ecosystem.
So, even though this type of starfish is moderately terrifying in its size and how it eats, they are crucial to the health of the ocean thanks to their diet!
Egyptian Sea Starfish
Then we have Egyptian Starfish which have a diet of sponges and snails as well as algae.
They are found in the Indian Ocean and are easily recognized by their sharp spikes on their surface.
They also have many colors, although mostly red and orange and can be found in coral reefs and on coasts.
They also have five arms, and are smaller, with a maximum size of 15 cm. They do tend to feed on invertebrates but are known for being omnivorous as well.
They are actually widespread and can even be found all the way from the Indian Ocean to Japan! As long as there is food there, they’re happy!
How Do They Hunt For Their Food?
Not all sea stars will feed the same, some will find food by trapping pieces with mucus beneath their arms.
Some will grasp onto their prey, everting their stomach onto their prey, so their digestive enzymes break their prey down
Some sea stars will have sensing abilities which will help them to find their prey, such as the leather star which has light sensing organs.
Starfish have a wide range of diets, but it totally depends on the type of starfish. Different starfish eat different things, but they are all pretty cool!
We hope you learned something new about these wondrous creatures!