red knobbed starfish

Red Knobbed Starfish (Protoreaster linckii) – The Ultimate Guide to Care, Diet and Habitat

The Red Knob sea star is also known as the red knobbed starfish or Linck’s Starfish. The scientific name for the red knob sea star is Protoreaster linckii. They belong to the Echinodermata phylum and the Asteroidea class. The red-knobbed sea star is also known as the Linckia Starfish, the red knobbed sea star, the Red Linckia, and the Comet Star. These are all common names for Protoreaster linckii.

The red knob sea star is a very interesting kind of starfish that is considered to be one of the best pets in the aquarium. They are not only beautiful, but also easy to keep. They will do well in any sized aquarium. They are not aggressive at all and quite sociable with other species of fish.

The red knob sea star, also known as the blood sea star or the Red Linckia sea star, is a large, eye-catching species that makes an attractive addition to many reef aquariums. It is one of the most popular species of starfish due to its appearance and size.

Size, appearance, and coloration

Red knob sea star or red knobbed starfish is one of the most beautiful-looking sea creatures. With the appearance of a star and its stunning red color, it can be a great addition to your tank. In terms of size, the red knob sea star can grow to about 17 inches in diameter. However, the average size for adults is about 8 inches.

The central disc is usually reddish or orange, with brown or black blotches throughout. The tips of each arm are usually white or tan, although they sometimes have brown blotches or stripes instead. It has five arms with tiny spines on its upper surface. The tips of its arms are slightly pointed, which gives it a star shape when viewed from above.

It has a dark red coloration with varying amounts of white or grey spots on the upper surface of its body and arms. It can be quite striking when it’s well fed and healthy. Often confused with the Chocolate Chip Sea Star (Protoreaster nodosus), which is commonly sold as a red knob sea star but is actually brown with white spots!

The red knob sea star is an attractive marine species with a vivid coloration, and it has a unique five-pointed radial symmetry. Its appearance makes it one of the most sought after marine invertebrates. The red knob sea star has five arms and has several ossicles or skeletal plates under its skin. Its mouth is located at its underside and has the ability to regenerate an entire arm if one is lost even after months of having lost it.

It comes in a variety of colors, such as red, orange, yellow, greenish or grayish. Its body has a unique texture and the arms are covered with small spikes.The red knob sea star gets its name from its typical range, which includes the Red Sea.

Habitat of the Knobby starfish

Red knobbed starfish
Red knobbed starfish

The red knob sea star can be found in the tropical waters of the Indo-Pacific region. They are usually found in coral reef areas and are also known to live on sandy bottoms. they also live in shallow lagoons, tide pools, and are sometimes found as deep as 35 meters underwater. They use their arms to walk across the ocean floor to find food, but they can not swim or crawl fast enough to escape predators. This is why they have evolved a few defense mechanisms to protect themselves. However, it can be found in a wide range of habitats.

Red knob sea star is a common species that lives on the rocky coast of the Red Sea. They are found in intertidal and subtidal zones, where they occupy an area of a few square meters. They prefer to live in shallow waters (up to 100 meters deep) and can be seen during low tide. They inhabit coral reefs, seagrass beds, mangrove swamps, tide pools, and rocky or sandy shores. This echinoderm is sessile, which means that it is attached to the bottom of its habitat with its feet, and moves using its tube feet.

This species can survive in both warmer and colder waters, but they are mostly found in tropical waters that are rich in oxygen. They can’t survive if they are exposed to air for a long time because they have gills instead of lungs; thus, they’ll die if exposed to air for a long time.

Diet of the red knob sea star

The diet of the red knob sea star is varied and consists of many different things.Mostly, they are carnivores and will eat fish, urchins, snails, clams, sea stars, crustaceans and worms. They also eat algae and other plant material as well.

The red knob sea star is also a scavenger and an opportunistic feeder. This invertebrate can eat dead or dying animals that it encounters as well as carrion or decaying plant material. The red knob sea star will rarely hunt live animals unless it is very hungry or small enough for it to catch. This species will also eat algae when available and may even attack live corals for their polyps.

They obtain their food from the water currents. They are opportunistic predators and feed on a wide range of animals. They can also feed on large animals too.

So this species of starfish are known to eat a wide range of foods, including both dead and alive prey. Some are scavengers, meaning they will feed on dead animals that have already died of natural causes. Others are predators and will actively hunt their prey.

Reproduction and Growth

This is where the red knob sea star gets its name from, as they can reproduce asexually by splitting in half. But they also have both male and female sex organs and will mate and fertilize eggs.

The eggs will hatch into larvae, which will float around for about 10 days before settling on the substrate. The larvae will then attach themselves using their tube feet and develop into juvenile sea stars. This whole process can take anywhere between 3 to 4 weeks to complete.

Juvenile red knob sea stars will grow quickly at first, but it slows down once they reach 2 inches in diameter. A full-grown red knob sea star can be anywhere between 5 and 10 inches in diameter, although there are some that have been recorded at 20 inches in diameter!

So the reproduction of the red knob sea star is very interesting as they have separate sexes, but they also have both male and female sex organs and will mate and fertilize eggs. Some species, however, reproduce in a different way, and this is called asexual reproduction. This is where the starfish can regrow lost limbs and develop new ones to form a new starfish.

Predator and threats to red knobbed starfish

The red knob sea star is a predator and can have numerous enemies that prey upon it. Predators include fish, birds, crabs, and larger sea stars, among others. Its main predators are those fish that can attack it from above when it is on the ocean floor. For example, triggerfish and trumpetfish are known to eat sea stars.

Sea stars attach themselves to rocks, coral reefs, and other stable surfaces and then move along to feed. They can pry open clams and oysters with their tube feet and strong arms. They also feed on slow-moving animals like snails, crabs, sponges, and worms.

Another main threats to red knob sea stars are pollution and overfishing by humans. The red knob sea star is also threatened by climate change, pollution and over-fishing. As ocean temperatures rise due to global warming, the animals begin to die off in large numbers due to bleaching (losing their color). This can be fatal for them if ocean temperatures do not return to normal levels quickly enough or if levels remain above what the animals can tolerate for extended periods of time.

Pollution is another threat to the red knob sea star population in some areas, particularly from agricultural runoff and oil spills.

Breeding Guide for red knob starfish

The red knob sea star is a great addition to any saltwater tank. It has a distinctive red color that makes it an attractive decoration for any home or office aquarium. The tank size for a red knob sea star should be 20 gallons or larger, with plenty of live rock for it to move around on and hide in.

They require a reef tank that has plenty of free swimming space, as they will have to move around in order to find food. They also require a sandy substrate because they tend to bury themselves when they are sleeping. Ideally, you should keep them with peaceful tank mates, and you’ll need to provide plenty of live rock for them to graze on algae.

When it comes to water conditions, the red knob sea star prefers warm water with a lot of flow. You should aim for between 75ºF (23ºC) to 82ºF (27ºC). The pH should be between 8.1 and 8.4 and the salinity should be 1.023 – 1.025%.

Lighting isn’t too important for these sea stars as they don’t need light to survive, but they will do better if you have low wattage lights over your tank so that they have some light during the day. No special filtration is required for these animals, but you should use a tight-fitting lid to prevent escapees.

red knob sea star Behavior and Tank Mates

Red knob sea stars are usually a very docile, peaceful species. They can be kept with a wide range of fish species that do not nip at the spines of the red knob sea star. They may get along with slow-moving fishes and will not harm them.

However, they might try to eat slow-moving shrimp and hermit crabs. The red knob sea star can also be kept in reef tanks because it doesn’t damage corals or invertebrates.

Knobby red starfish
Knobby red starfish

red knob sea stars live a solitary life and prefer to be alone. Having said that, there are some fish that can be kept with the red knob sea star without any issues. These include Clown Fish, Hawkfish, Angelfish, Damselfish, Dwarf Angelfish, Butterflyfish, and Tangs.

The red knob sea star is not aggressive towards other animals and will not harm them unless they are potential food sources for it. It is important to remember that if you do choose to house more than one Sea Star together in an aquarium that they should be of similar size since smaller ones may become meals for larger ones.

The red knob sea star belongs to a group of sea stars called Brittle Stars. They are scavengers that spend most of their time buried in sand or mud with only their arms visible. These arms are extremely flexible and can be used to catch prey such as clams, crabs and snails. However, unlike other sea stars, they will not attack healthy prey.

Cool Facts about the Protoreaster linckii

  • The red knob sea star is a beautiful sea creature that is endemic to the Red Sea. They are also known as the Linckia starfish and are commonly found in shallow waters.
  • red knobbed starfish don’t have brains, so they cannot think or feel pain like humans do. Instead, their nervous system is spread throughout their body and controlled by hundreds of nerve cells called ganglia.
  • The red knob sea star has a unique feeding habit. They feed by everything their stomach and digesting the prey outside of the body. This allows them to eat prey that is larger than their mouth opening which is very small compared to the rest of its body.
  • The red knobbed starfish has a wide range of predators including fish, seabirds, other sea stars and even humans
  • When a starfish is at its best, it can be a spectacular visual treat. The bright red of the red knob sea star is absolutely stunning and can be the centerpiece of any tank. 

Red Knob sea star-Frequently Asked Questions

Q1. What kind of starfish is red?

A red knob sea star is a type of marine invertebrate that is commonly known as a “starfish”. There are many different types of starfish that live in oceans all over the world, but most people recognize them by their bright red color. Some species have blue or purple shells instead of red ones on their backs. These animals are not true fish because they don’t have fins like real fish do. Rather than fins they have five arms that come straight out from their body at right angles with each other.

Q2. What does a red knobbed starfish eat?

The red knob sea star is a carnivorous hunter that feeds on a wide range of animal prey, including mollusks, worms and crustaceans. In the wild, these creatures can be seen in tide pools, where they hunt down mussels, clams and other small invertebrates.

Clams are their favorite food, and the sea star has become quite efficient at getting their meal. It starts by prying open the bivalve shells with its suction-cup-covered arms. Once open, it pushes its stomach into the shell to digest and eat the clam.

Q3. Are red knobbed starfish hard to keep?

Red knobbed starfish are not difficult to keep. They can easily be kept in a well-maintained home aquarium. However, if you are looking for the correct conditions for your red knob sea star, it is important to know that they prefer to live in a marine environment with some live rock and clean water. Also, the sandy substrate is not a requirement for them, so you can easily make do without it

Red knobbed starfish are best kept in well-established saltwater aquariums that have a mature live sand bed and live rock. They will die if not given enough to eat, or if their aquarium water conditions become poor. red knobbed starfish are best kept in well-established saltwater aquariums that have a mature live sand bed and live rock.

Q4. How do you make your red knob sea star happy and healthy?

The red knob sea star is a great aquarium pet, because it can survive for quite some time with little attention and care. However, if you want to keep your sea star happy and healthy, there are a few things you need to take into consideration these are water parameters, feeding process, tank size, tank mates, filtration, lighting requirements, proper diet, temperature condition, etc.


Red knobbed starfish are really pretty docile, make a great low maintenance pet, and are affordable to boot. Starfish are fascinating creatures that, despite their scary and intimidating appearance, don’t require much care. With a little patience, an understanding of their requirements, and a willingness to invest some time into your starfish—you might find that they are worth the time and effort you spend feeding them, cleaning their tank, and making sure they stay healthy.

Leave a Comment

Your email address will not be published. Required fields are marked *