About Selecting Brittle, Serpent & Basket Stars
Phylum: Echinodermata
Class:Ophiuroidea
So what is the difference between Brittle and Serpent Stars? Even though the common Brittle/Serpent name is applied to these starfish when identifying one group from the other, the basic distinction that sets them apart is that Brittle Stars have spiny arms and Serpents have smooth ones.
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With more than 2,000 described species found in tropical waters worldwide, Brittle and Serpent Stars are keenly sensitive to light and will immediately seek shelter when exposed to it. Being nocturnal scavengers that feed on detritus and debris at night, they can usually be seen sticking partially out of their hiding places inside or under rocks, corals and other living organisms. These animals hunt by their keen sense of smell and touch. From our experience when food is dropped into the aquarium, the arms of the many baby starfish hiding in our live rock start protruding out and begin to excitedly wiggle around. We once had a full grown Spiny/Black Brittle Star (Ophiocoma erinaceus) that would come out of hiding to look for the food source, sometimes even with the tank lights on. It would search out and find it on its own, and if not we would directly put the food (usually shrimp chunks) into its arms with long-handled tongs if the fish, hermit crabs and other tank inhabitants ate it before the brittle star could get to it.
It is quite common to find these starfish hitchhiking in on live rock, and most often this is how they seem to appear out of nowhere in an aquarium. To defend themselves from predation they will break off arms, which are quickly regenerated, and this combined with the fact they are probably one of the fastest moving of all echinoderms, this allows them to make their escape.
Starfish in the class Ophiuroidea have separate sexes that reproduce by the synchronized release of eggs and sperm, where fertilization takes place in the water. The eggs hatch into free-swimming larvae that drift as plankton in the current and finally settle on the bottom and transform into juveniles. They grow to various sizes, with some getting quite large, like the White Brittle Star (Ophionereis sp.), and come in a very wide range of colors from dark to light shades of black, brown and tan, to light pastel and bright shades of pink, purple, blue, red and orange.
Most all Brittle and Serpent Stars of the genera Ophionereis, Ophioderma, Ophiocoma and Ophiarachna are good non-aggressive reef tank scavengers, with the exception of the very controversial Green Brittle Star (Ophiarachna incrassata), and possibly other Ophiarachna sp., because it has been reported to attack, capture and eat unwary fish. Be sure to research the size potential on any of these starfish before buying them as well, as some can grow quite large.
As far as Basket Stars, these nocturnal starfish are seldom kept in captivity because they require specialized large aquariums and a precise diet and feeding technique.
To learn more about the natural history, ecology, biology, and other characteristics of starfish members of the class Ophiuroidea and choosing them, we recommend the following reference resources:
- "Scavengers for Marine Systems" (refer to The Spiny-Skinned Animals section) by Robert Fenner.
- "Brittle & Basket Stars, Class Ophiuroidea" by Robert Fenner.
- Brittle & Basket Star FAQs from Robert Fenner.
- More Starfish Care & Photo Resources
- "Hawai'i's Marine Creatures: A Guide To Hawai'i's Marine Invertebrates" by John. P. Hoover.
