Care, Diet, Tank and Mates

Care, Diet, Tank and Mates

We’re thrilled to present you with our friendly guide on caring for the fascinating Brittle Starfish. These graceful and mesmerizing creatures are a captivating addition to any saltwater aquarium, and we’re here to provide you with some essential insights to ensure their well-being. 

These starfish are incredible scavengers, constantly searching for leftover food and detritus in your tank, helping to maintain a clean and healthy environment. So, let’s plunge into the captivating realm of these enchanting sea stars and uncover the secrets to crafting an ideal habitat for their well-being!

Species Summary

Like the stars in the sky, the Brittle Starfish comes out at night. This five-limbed invertebrate is a born scavenger that spends its evenings searching the bottom of the tank for odds and ends to eat. Brittle Starfish are absolutely fascinating to watch in the water due to their slinking, snaking motions. 

Known under the scientific name Ophiuroidea, this wonder is found abundantly in reefs throughout the waters surrounding the Caribbean, Africa, Fiji, Eastern Asia, and Australia. They are common sights in the waters stretching from Southern Japan to the Great Barrier Reef.

Brittle Starfish are often called Serpent Starfish due to a long, slithery appearance that can make their five legs resemble snakes. Other names used include Fancy Brittle Star, Mosaic Brittle Star, and Painted Serpent Starfish.

Two Interesting Facts:

  1. The Brittle Starfish gets its “brittle” name from the fact that it will break off an arm in an instant as a defense mechanism against predators.
  2. The tiniest varieties of Brittle Starfish actually use a form of “breaking off” called fission to make copies of themselves for reproduction.

Author Note: Brittle Starfish are much faster than starfish, urchins, and other echinoderms. Their incredible speed allows them to evade predators by darting under rocks when they sense danger moving through the tides. Despite their speed and wit, Brittle Starfish are generally considered docile creatures.


With several varieties of Brittle Starfish roaming the world’s sea floors, it can take a bit of discernment to know which type you’re dealing with. Here’s a crash course on the appearance of this species.

  • Brittle Starfish. The popular Brittle Starfish is characterized by a classic five-segment radial symmetry. This creature is unmistakable due to its five spiny, flexible arms that connect to its disc-like core. These arms are essential for grabbing and pulling substrate, rocks, and sponges. They’ll even use these arms to speed through the ocean! The mouth of the Brittle Starfish is located on the underside of its central disc that connects its limbs. This is where you’ll find a jaw consisting of five teeth.
  • Banded Serpent Starfish. This is a subset of the species that is known for its long, thin arms with remarkable brown and black bands. While the Banded Serpent Starfish is typically gray in color, it’s not uncommon to see stars with cream or orange coloring.
  • Mini Brittle Starfish. Also known as Baby Brittle Stars, Mini Brittle Starfish are busy sand sifters that may first appear like nothing more than tiny legs poking out from your tank’s rockwork. Capable of fitting on your finger, these tiny stars resemble worms. Their bodies can be both plain and striped. They often make “surprise pets” after hitchhiking on rocks purchased for aquariums.
  • Green Brittle Starfish. You can easily identify this starfish by its pastel-green coloring. This beautiful shading covers its disc-shaped body and worm-like arms. The green is broken up slightly by spine lines running down the arms that can appear white to yellow.


Most Brittle Starfish have a lifespan of eight years. However, it’s more realistic to expect a “good run” to last for four to five years. Keeping optimal tank conditions plays an important role in helping this creature to max out its lifespan potential.

Average Size

As a slow grower, the Brittle Starfish reaches its maximum size potential at around 4 years old. The size of a full-grown starfish can depend on which variety you’re dealing with. It’s common for the Brittle Starfish to reach an average size between 12 inches to 20 inches from arm to arm.

The popular Banded Brittle Starfish typically grows to reach 6 inches to 9 inches. Of course, the petite Mini Brittle Starfish can only grow to a diminutive size of 1.25 inches.

Brittle Starfish Care

While Brittle Starfish can vary greatly in appearance, the same tank conditions and care requirements are generally used for all varieties. The biggest requirement is that a Brittle Starfish needs to be introduced to an established, cycled tank that won’t shock them with sudden changes to temperature, pH, and salinity.

Tank Size

These creatures need lots of hiding places and room to roam! The minimum tank size required when housing a Brittle Starfish is 20 gallons. Go for 50 gallons if you can! When housing multiple Brittle Starfish, the tank size needs to be expanded to accommodate all of the hiding spaces needed.

Water Parameters

  • Water temperature: 72 to 80°F
  • pH levels: 8.1 to 8.4
  • Water hardness: 8 to 12 dkH
  • Specific gravity: 1.021 to 1.025

Tank Setup

The Brittle Starfish’s low tolerance for nitrates means that tank conditions must be consistent. The goal is to replicate the sand, mud, and sizable rocks found in the Brittle Starfish’s natural habitat inside a tank. This critter needs to be able to hide within rock crevices to thrive.

Aside from water parameters, substrate is the most important factor in keeping Brittle Starfish healthy and happy. 

Brittle Starfish also treasure the ability to relax in sand beds with their snake-like arms spread wide apart! While the Brittle Starfish doesn’t have any rigid lighting requirements, they don’t appreciate bright, harsh lights. This eyeless creature can sense strong light that will send it seeking shelter under the closest rock. 

Author Note: If you’re using LED lighting for tank mates, be sure to turn off the lights in the evening to encourage your shy Brittle Starfish to emerge for its nightly feeding frenzy.

Are Brittle Starfish Reef Safe?

The short answer is yes, Brittle Starfish is a reef-safe addition. As omnivores, Brittle Starfish should be suspected of being capable of eating anything. That includes corals! However, well-fed Brittle Starfish are unlikely to attack coral. It’s still possible for a particularly aggressive Brittle Starfish to “go rogue” regardless of how abundant its preferred food sources are. Careful monitoring is needed when pairing Brittle Starfish with corals, crabs, snails, and shrimp.

Common Possible Diseases & Prevention

Brittle Starfish are vulnerable to parasitic attacks from protozoans. These invaders can easily infiltrate a Brittle Starfish’s gonads and digestive tract. Additionally, the Brittle Starfish can also be bombarded by small crustaceans and polychaete annelids that work their way into its bodily systems to cause pain and discomfort.

The solution is to quarantine all new additions to the tank that could be carrying parasites from their previous homes.

What Do Brittle Starfish Eat?

As bottom feeders, Brittle Starfish are opportunistic when it comes to their carnivorous pursuits! While the flexible arms of the Brittle Starfish are masterful at scooping up prey, this creature gets a fair amount of its nutrition by swiping zooplankton and detritus that become trapped in its spines. 

Author Note: Once night falls, these determined little stars will scour the tank for leftovers they can claim with their arms. Think of them as the tank’s nightly janitorial service!

A Brittle Starfish won’t be able to meet all of its own nutritional needs by scouring the bottom of the tank. In fact, relying on a self-service approach to feeding is a surefire way to create a nasty, aggressive star that lunges at vulnerable tank mates.

When hungry, these starfish have even been known to go after their own arms! Imagine having a starfish that looks more like a circle? A good diet for a Brittle Starfish will consist of finely chopped pieces of shrimp, clam, muscles, and silversides (sand smelts). The enticing aromas of these bits will actually draw your starfish out to create some fun mealtime bonding for owner and star!

Behavior & Temperament

The Brittle Starfish’s personality is complicated. Expect to see a Brittle Starfish spend its day hiding under rocks or sand. At night, the star emerges to scavenge and hunt. This nocturnal behavior serves as a form of preservation against reef fish that will gladly slurp up those long, linguine-like arms. While the Brittle Starfish is fast, it’s not quite fast enough to be fearless.

The Brittle Starfish is generally viewed as a gentle and docile creature, but a stressed Brittle Starfish can be an unpredictable force. They will pick off vulnerable tank mates if their needs aren’t being met. For this reason, tank owners need to be prepared to watch their stars closely for any hints of behavioral changes that could put little snails, shrimp, crabs, and corals at risk.

Brittle Starfish Tank Mates & Predators

Brittle Starfish can be both aggressors and victims within the same aquarium environment. Unfortunately, a fair number of common tank inhabitants find Brittle Starfish incredibly tasty! For this reason, they should never be paired with invertebrate-munching species that include boxfish, arrow crabs, parrotfish, pufferfish, triggerfish (like the Clown Triggerfish), and harlequin shrimp.

Plenty of attractive, enjoyable fish species have no problem sharing a tank with Brittle Starfish. These invertebrate-friendly fish will gladly create crumb trails that allow little stars to sweep up tasty leftovers while traversing the tank’s substrate. The best tank matches for Brittle Starfish include:

Author Note: All of the rules of reef fellowship go out the window when it comes to the Green Brittle Starfish. The nickname for the Green Brittle Starfish is the “green monster” due to its reputation for being a nocturnal predator. When shopping for Brittle Starfish, the general rule is that smaller varieties tend to be less aggressive.


The fast breeding of Mini Brittle Starfish is an exception to the rule! (see author note below) In fact, cases of other types of Brittle Starfish reproducing in tanks are rare. The Brittle Starfish reaches sexual maturity at the advanced age of 1.5 to 2 years old.

What makes the reproduction cycle of the Brittle Starfish so mystifying for humans is the fact that deciphering between male and female stars is extremely difficult! When breeding, the male Brittle Starfish will climb to the highest point on the reef with its central disc extended out to release gametes into the water to reach females.

The fertilization that occurs is external fertilization. Once hatched, fertilized eggs become larvae that undergo two stages of metamorphosis. During the first stage, a symmetrical form emerges to simply swim around the tank. During the second stage, a figure resembling an actual Brittle Starfish nestles into the substrate.

Some Brittle Starfish varieties have also been observed “brooding” their young internally instead of reproducing through a two-stage transformation following the egg stage. In these cases, developing stars are nurtured inside a pouch. The parent then releases the juveniles when they are ready to be independent in the water.

Author Note: The reason why Mini Brittle Starfish reproduce rapidly compared to other star types is that they use asexual fission reproduction. This means that these stars actually regenerate using a single piece of a body part that has split away. The Mini Brittle Starfish essentially clones itself!

Wrapping Up

We trust that this guide has equipped you with invaluable insights on nurturing the magnificent Brittle Starfish. A cool note to remember is that these starfish have the remarkable ability to regenerate their arms if they are damaged or lost. This incredible regenerative power allows them to heal and recover from injuries, making them highly adaptable and resilient creatures. 

By providing them with a suitable environment, regular feeding, and avoiding aggressive tank mates, you can ensure the well-being and thriving nature of your Brittle Starfish. So, embrace the wonder of these delicate sea stars and don’t forget to tag us on Facebook when sharing photos of your new star! 

If you are looking for more starfish you can learn about the Chocolate Chip Starfish!

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