What do Starfish Eat? (Not What You Expect)

All across the world from beautiful coral reefs to shallow tide pools one can find starfish; the small but often beautiful animals so named for their remarkable resemblance to beautiful shapes in the sky.

Coming in a variety of colors, starfish live in almost every part of the ocean and can come in an even more impressive array of shapes. Some can have as many as fifty or more limbs! They prefer shallow waters the world over, keeping them well within range of people, but there are many things that people don’t know about these incredible animals.

Some don’t even realize that they’re animals at all, and like all animals, they need food to survive. But at a first glance it may seem impossible for them to eat. They don’t have any possible mouth, or an apparent face, so how do they survive, and what are they?


Starfish Overview

First a little explanation can make it a little clearer what exactly a starfish is. Despite their name, they aren’t fish at all!

Rather, they belong to a group of animals called Echinoderms. These incredibly successful creatures come in thousands of varieties, and they make their homes everywhere from the coldest arctic waters to the warmest shallow seas, and some even call the deepest depths of the ocean home.

Their bodies are quite different from humans, and they don’t even have blood, instead circulating their nutrients with seawater that they let flow through their bodies so they are effectively the same chemical makeup as the water around them. They don’t even have a heart or similar muscles.

Some organs though like a stomach, muscles, and even light sensitive structures like eyes on their arms make them capable without too much complication. This simple build actually gives them incredible resilience.

Even being cut so badly they lose a limb doesn’t kill them, and instead they regrow the lost appendage as if nothing ever happened, something most animals on earth could never hope to do. In fact cutting them in two often results in two new starfish. Being able to regenerate gives them a great advantage when being targeted by predators, as happens often in the ocean due to the many animals that want to make a meal out of starfish.

These predators include birds, seals, sharks, fish and even other starfish, along with many others who may want a quick and easy meal.

What Do Starfish Eat?

When it comes to eating on their own, Starfish are actually quite diverse in their diets, as living all across the world exposes them to all kinds of different food sources.

Generally most of them prefer to eat whatever kind of food they can find. Common foods available to them include microscopic organisms, underwater plants, dead animals, and even other starfish. How they eat it depends a lot on the meal they’ve chosen.

A mouth isn’t visible on a starfish, but they do have an opening for food, though they don’t push the meal inside. Rather, they grab a hold of what they want to eat and push out one of their stomachs to cover the food.

While their stomach is on the outside, it starts breaking the food apart for them in the place of teeth and muscles that other animals have. Generally they can only break apart things that are already softened, so animals with protective armor like a clam will need their shells to be held open by their many arms so they can get to the soft meat inside. Breaking it down with the acids in their stomachs, they will then bring the organ back inside once it’s full, and leave what remains of the meal they can’t digest.

By sending out their stomach, they can actually have huge quantities of food at once!

Turning it into liquid before they ever eat it allows them to take in animals that are often bigger than them, and that includes the fish and plants some of them choose to eat. A second stomach helps to really break food down so they never have to waste any potential nutrients, but this stomach stays inside of them while it works.

These clever tricks have helped starfish settle on almost part of the planet, as they can almost always find something to eat.

How Does A Starfish Protect Itself?

When it comes to being hunted, they are not defenseless however. While they may appear to always be still, they have hundreds or thousands of tiny limbs beneath them that crawl them across the ocean floor, and it actually gives them a powerful grip they can use to climb rocks almost vertically. This helps them to escape predators and get to new places to find food, although they often move so slowly you have to wait a long time to actually see it. It can also help them squeeze their flat bodies beneath stones to hide.

Their primary defenses against being eaten tend to be more complex. Some of them secrete foul tasting chemicals that predators don’t like to eat but aren’t actually harmful, and a single taste of these bad flavors will have most animals dropping them, if they ever try to pick them up in the first place. Others go further and produce deadly toxins.

Some of them ooze these deadly chemicals all the time, and in some cases it’s powerful enough to kill or severely injure humans, entering the blood with a powerful and painful sting that can do incredible damage!

Beyond that, most starfish are simply quite solid and cover themselves in thick skin like armor that predators have a hard time breaking through. A few cover these plates with sharp points, and some even use their toxins in them to more seriously hurt predators, mixing and matching their defense.

Losing arms is actually a way to save themselves, as it can confuse or even satisfy a predator and allow them to escape.

How Do You Keep Starfish Healthy

In captivity, starfish are no less likely to try hunting, and they need regular and natural food to keep them happy and healthy.

Because they require salt water and salt water is something very hard to keep clean, only an expert should try to keep them as pets. In fact, you would need to be an expert in the animal as well as fish tanks to have one in your home that would be alive and well.

A very large tank is an expensive but essential must in order to get started. However, a proper setup is no good if it doesn’t match the specific needs of the animal you bring home to live with you.

Starfish come in thousands of species, and each one has its own unique requirements. Some of them are predators while others only like plants, and some want frigid water while others will want cold. Still others will be fine living in groups while others will eat anything you put in a tank with them. Careful research is a must to ensure that the considerable amount of money you are spending doesn’t go to waste on a mismatched setup that kills your precious new pet before you ever get a chance to enjoy them.

In fact that could kill them as well, as eating fish that’s not natural for them can be fatal. If the species allows it, you can actually have fish in the tank as well as starfish, and the two can live together quite well if you pick them out and take care of them.

What Do You Feed A Starfish In Captivity?

Once everything is established keeping a starfish healthy is closely connected with that they eat, the same as any animal, and where they live.

Pay close attention to setting up your aquarium with coral, rocks, plants, or whatever else your starfish calls home in the wild. Once they are settled they will eventually need to eat. A starfish that just grazes across the sand will need far less supervision than one that wants to capture and break open clams to get at their insides, but both will need supervision as well as variety to keep their diet healthy.

No animal can just eat one thing all the time and be okay. A predatory starfish can be provided clams and mollusks from pet stores that typically sell them as food, but washing them and ensuring they have no disease before you feed them is critical.

Illness can be spread surprisingly easy in the water, so no new animals should enter the tank without being cleared first, even if they’re just going to be food for something else. A reputable food supply store will always be a good investment for pets of all kinds, even if they live in a small tank.

Starfish that prefer plants can be a little easier, as they can actually eat things both natural to their environment and otherwise. Plant trimmings from your garden can even work if you know it doesn’t contain chemicals to hurt them. It can also be much cheaper as well, as something that you can buy at a grocery store is much cheaper than specialized food from a pet store and can do the job just as well, and may actually supply your pet with some much needed enrichment.

What Do Starfish Eats in Aquariums?

The habits of your starfish and how often it eats will vary a great deal depending on the species you get. Some of them prefer to move about during the day when there are bright lights and warmth, while others are more nocturnal and only like to be active in the darkness. This schedule will affect when they want to eat and how often.

Starfish in colder environments also typically prefer to eat less often, while those from warmer waters will typically expect food almost every day or every other day. They can even switch these schedules on their own if they believe what they want is more likely to be available during the day or the night.

The simple eyes on their tentacles allow them to tell the difference between day and night.

While they have no way to tell you that they’re hungry, just putting some food in the tank will let them feed themselves if they so choose, and you typically don’t have to worry about them feeding too much like fish.

In fact, some of them will help clean the tank they live in by eating algae and debris left behind by other animals that may live with them. This kind of circle of energy is a great way to mimic the wild, which is the ultimate goal of any kind of captivity, as it makes the animal far healthier when it lives as it was always meant to.

Should You Have A Starfish As A Pet?

Overall, starfish are animals that live almost everywhere and eat almost anything depending on where they live, and while they are strong and durable animals they still need to be taken care of if they are to be happy and healthy living a domesticated life.

The most important thing is always research. Research on the kind of starfish you want to keep, where it likes to live, and what food it likes to eat will help you keep a much healthier pet that will be with you much longer.

It can even be a good companion to fish you already own. While chopping vegetables and buying and cleaning clams may not be what you expect to come with owning a starfish, going out of your way to care for the pets you buy will always be required in order for you to be a good pet owner, and starfish can certainly be very rewarding pets if you work to take care of them.

They can teach you a lot about the ocean, as they are some of the most important animals that live in it, their very presence helping to balance out the environment and keep it healthy. Having more of them actually helps the whole ocean live healthier, and keeping one as a pet can help you grow a better understanding of just how valuable these incredible animals are.


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