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What Do Starfish Eat? How To Feed Starfish

Sea stars also called starfish are omnivorous species and they can be opportunistic carnivores. So they eat That means, they eat both plants and animals. Below is a list of what Starfish Eat.

  1. Mollusks (such as clams, oysters, and mussels)
  2. Crustaceans (such as shrimp, crab, and krill)
  3. Small fish
  4. Dead or decaying matter (scavenging)
  5. In captivity, thawed marine invertebrates such as mussels or shrimp, or commercial sea star food pellets.

Their food preferences depend on where they live. But, If you are willing to keep sea stars in your aquarium, you can’t always feed them with snails or shrimps. Don’t worry, I am here to explain to you different ways t feed your starfish.

sea stars eat

First, we have to find out about their feeding behavior.

How do starfish eat?

The main question is starfish do not have any eyes, so how do they find food?  Yes, they do not have eyes. But at the end of their every limb, there is an eyespot Sensitive to light, which helps them to find food while feeling their surrounding area.

eyespots star fish

 How did they move to find food?

Under their limbs, there are thousands of tube feet; each helps them move around the ocean bottom and grab food from them. Also, this grouping can help them catch food and pry their shells open.

tube feed for moving around

How do Starfish digest food?

To this, starfish have two stomachs called namely cardiac and pyloric. One prey is caught; they sent the cardiac Stomach inside of the prey, Release digestive enzymes, and digest part by part. Then pyloric Stomach steps in and absorbs digested nutrients. They are experts at doing this process. They can digest even larger Animals using this method.

starfish stomach
starfish stomach – image source – interest
Credit to : Vancouver Aquarium

Are Starfish really fish?

Although these beautiful animals are called starfish they are not fish. Starfish belong to the big animal group called echinoderms and they are living in the sea. As the name implies, they have a star-shaped body with five fingers. In the world, there are around 1500 species of starfishes. Some of them can even live in very deep waters. According to Wikipedia, some starfishes have been found in 6000 ft deep waters of the sea.

They have a very colorful body. Therefore starfishes are a very attractive addition to an aquarium. But, you can’t just keep them in your freshwater tank like other freshwater fish. As the name implies this unique animal is only found in the sea. To keep them alive, you must have a seawater tank. A minimum salinity level of 1.02 is required for sea stars. Also, the pH of the water should be in the range of 8.1 – 8.4.

What do sea stars eat

What sea stars eat in nature/ocean?

In nature, starfishes are strategical hunters. Since they can’t move like other fishes, they always target slow-moving animals. They just stay calm and seek the slow-moving animals around them. Especially if some animal is injured or dead, Starfish will take care of the dead body.

In nature, corals, small shrimps, small snails, mussels, and clams are their common meals. The starfish’s diet in the ocean depends on their species. Because some are predators, some are scavengers. Below is the list of popular starfish and what they eat.

Chocolate Chip Sea Star (Protoreaster nodosus)

This one prefers a meaty diet. Therefore they are predatory starfish species. If they are given a chance, they will eat a wide variety of coral and other reef invertebrates in the ocean.

Chocolate Chip Sea Star

Blue Sea Star (Linckia laevigata)

This one here is a scavenger, so they feed on anything found in the bottom. These blue beauties normally do not feed on live corals. So they can be kept with your beautiful corals.

Blue Sea Star

Red-Knobbed Sea Stars (Protoreaster lincki)

Although they seem like a predator, they prefer algae, so you can see them scavenging for algae in the ocean. If you want to keep them in your tank, they will benefit from a vegetarian diet.

Red-Knobbed Sea Stars

Predatory/carnivorous starfish

Starfish like to lay low. So, they normally borrow in the sand or are attached to rocks. As they are not active species, they hunt for slow-moving animals such as sea urchins, plankton, snails, sea cucumbers, mussels, clams, anemones, and coral polyps. Do you know that? this type of starfish can eat up to 150  clams per month. yeah, I am not joking here. Some of them are really like clams.

canivorus star fish
carnivorous starfish (image from the study. com)
canivorus star fish eating fish
Carnivorous starfish eating fish (image from reddit. com)

Scavenging starfish

These starfish scavenge for rotting material in the shallow ocean. But the thing is, this rotting food is low in nutrition. Therefore some of them scavenge by drifting in the water to find more food. So they can feed on floating material too.


How to keep starfish in the aquarium?

The starfish is a perfect addition to your reef aquarium. But it can be very high maintenance because they should be monitored very closely. It is essential to keep track of their diet, water quality, and tank size. When it comes to feeding, you need to do research, depending on your starfish. Because some starfish an easily fed, but some can be difficult.

When Considering tank requirements, the minimum tank requirement is 100 gallons, and keeping them in Small tanks can stress them. This is the most common reason for starfish death in aquariums. Also, do not forget to add the bottom substrate with rocks so they can scavenge for their food. 

Related: Sea bunny | Super Interesting Facts You Must Know

How to feed sea stars at home? What do sea stars in aquariums eat?

Unlike other fish varieties, you can’t just feed them with fish food or flakes. They will not even touch them. Always remember depending on what species of Starfish you have in your tank, the food habits vary. If you are a beginner in fish keeping or if you have never maintained a saltwater aquarium, do not buy Starfish. They need far more care than normal aquarium fish. 

Some starfishes can feed on algae. So they will eat the growing algae in the glass of your tank. Most aquarium keepers feed starfishes with frozen food varieties like frozen shrimp and frozen prawns. Even chopped sponges are a good choice. 

Some varieties of sea stars can feed on vegetables. They will accept boiled green vegetables, spinach, and kale.  Different verities have different requirements. So, before buying a starfish, always do research about their food requirements. Not all stars eat vegetables. So, don’t force them to eat things that don’t like.

star fish in home aquarium

How many times do you need to feed starfish?

Usually, they need to be fed every 2 to 3 days. Feeding frequency depends on the type of your starfish. So you need to do specific research on your starfish and make sure you do not overfeed or underfeed starfish. Best to prepare a feeding schedule for your specific starfish. Which makes it happy and active in your aquarium.

A good technique is to find if your starfish are hungry by placing a piece of food near them and observing how fast they eat it. If they eat it fast we can consider that they are hungry and increase the feeding frequency. If they are not interested in food you can slightly decrease the feeding frequency to make sure you are not overfeeding them. Also if you’re feeding mollusks that you got from market place make sure they are washed properly to flush out any toxins, because these mollusk toxins can make your starfish sick.

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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.