Feather Starfish: Care, Diet, Are They Poisonous?

Crinoids, or feather starfish, aren’t actually starfish but they are one of the oldest and most primitive species on earth. Their name comes from how they share similar characteristics to starfish, which only makes sense since they are cousins. What makes these amazing creatures a wonder are their arms, which seem like actual feathers protruding from numerous appendages.

In fact, they can have as many as 200 arms, allowing them to blend in with the environment and hide. These arms appear as bright and vibrant plants or fern fronds and, like their relatives, if an arm sustains damage, it can regenerate itself. 

If you are considering adding one to your home aquarium, there are three things to know with owning feather starfish, care, diet, and their toxicity.  Being meticulous about their requirements will be the keys to their survival.

What is the natural habitat for feather starfish?

They hide in plain sight among bright anemones and corals during the day, anchoring to the seafloor substrate. These gorgeous yet alien-like creatures live in colonies within the seas and oceans all over the world in both shallow and deep water. Some can live at depths as deep as 30,000 feet.

They love warm, shallow water with a few species residing in colder waters. They require the right surface for their feet to move over. Feather stars, which are different than feather starfish, live in areas with strong currents and don’t need to attach themselves to a substrate.

Are feather starfish reef safe?

Feather starfish are not reef safe. They will eat any and all small invertebrates they can get their arms on, including coral polyps. They usually eat these in a single bite and can easily wreak havoc in an ecosystem.

Feather stars are also very difficult to remove from the aquarium because of their shape, they will tuck in their arms and legs tightly, making them nearly impossible to capture.

How big are feather starfish?

The feather starfish is remarkably small in comparison to other sea creatures. The maximum size of one of these creatures is only about 8 inches wide. They are usually found in shallow waters where they use their tiny, branching arms to cling to objects such as coral and sponges.

What’s the difference between a feather starfish, sea lilies, and a feather star?

Many crinoids, like feather starfish, develop stalks to attach to the seafloor when they’re young. But, they lose these appendages as they get older which allows them to swim free. If the stalks remain into adulthood, they become known as sea lilies.

The ones that lose their stalks at maturity are feather stars. Feather stars still attach to a substrate when needed with a little set of legs called cirri. At night, they swim around in the ocean’s strong and powerful currents.

Are brains part of feather starfish anatomy?

No species of starfish has a brain, not in the way humans think of it. They have around nerve cord that encompasses their digestive area. It’s not shaped like a brain found in most vertebrates, but it is responsible for many of the starfish’s activities.

All starfish have something like a memory, but it is more of a learned response and they have a sort of social caste system. There is evidence of starfish communicating with each other when they hunt for food together. So, these behaviors indicate a form of intelligence that requires planning and organization.

What are the tank and water parameters for a feather starfish?

Feather starfish require shallow water and a constant flow of water currents with very rocky substrates. You have to recreate these conditions to perfection for the animal to thrive. This is what makes them very difficult to care for.

What are the requirements to replicate their natural environment?

They need rocks, coral, or sponges for feeding and attachment. Feather starfish do not tolerate any changes in water temperature and chemistry levels. To ensure you recreate their natural habitat, study the body of water where your particular variety comes from.

What poses a threat to feather starfish in an aquarium?

Any copper added from fertilizers or fish medication will kill them on contact. Other parameters, like salinity, must remain at 1.025 at all times. Things like oxygen, pH and etc will vary depending on the kind of feather starfish you have.

Sudden fluctuations in the water will cause them great distress and can result in a shedding of their arms or even death. Sometimes, though, if you do manage to be perfect with their living conditions, they can still die without explanation.

How old do feather starfish get?

In the wild, they can live up to 35 years old. But, in an aquarium setting, their lives shortened. It really depends on how well they adapt to the tank, a proper diet, and an owner’s attentiveness.

What do feather starfish eat?

Feather starfish have a very basic diet. They eat plankton, brine shrimp, and copepods along with other small detritus and micro morsels. But, they do clasp onto clingfish and other crustaceans from time to time.

What is the process of how feather starfish eat?

Feather starfish use their limbs to grab nutrients and food from the seafloor and the constant water current, sending plenty of food in their path. The arms have several tube feet moving and operating like sieves for the surrounding water. The anus of a feather starfish is in close proximity to its mouth and it doesn’t have a stomach.

Here’s how the eating process works:

  1. The independent, fringed arms have little tube feet that secrete mucus, which gathers nutrients floating through the water.
  2. The foot farthest away grabs the mucus food ball from foot right underneath it.  This bundles the food into a ball before it’s transported into the mouth.
  3. Then, a ball of food travels through each foot along the arm. This process creates a bolus of food that gradually gets bigger as it travels up the arm, foot by foot.
  4. This bolus attaches to the tube feet which are then moved to their mouth and enters a horseshoe-shaped digestive tract. 

Are feather starfish known to be poisonous?

Feather starfish aren’t poisonous. So, you can touch them without experiencing any issues. But, if your cat or dog eats one, it could cause them severe nausea and vomiting along with a host of other digestive issues.

Owning Feather Starfish

Indeed, feather starfish are one of the most beautiful animals in marine biology as well as one of the oldest species on earth. Their surprising and magnificent appearance makes a beautiful addition to any tank. But understanding how they live and what they require will help to ensure they live a long and full life in your home aquarium.

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