News / Species Spotlight / Serpent Star (11/04/15)

Serpent Star



Serpent Stars
by: Kevin Gaines

Taxonomy

  • Class: Ophiuroidea (Brittle Stars)
  • Order: Ophiurida
  • Suborder: Chilophiurina
  • Family: Ophiodermatidae
  • Genus: Ophioderma
  • Species: Over 25 species
Description

Serpent stars are truly amazing animals. Often they are only seen as smooth long arms protruding from rocks or other hiding places. The name Ophio = snake in Latin and is derived from their snake-like arms and sinuous movement. While there are over 2,000 described species within this class, we will focus on the genus Ophioderma, which is a reef-safe scavenger. These echinoderms are closely related to sea stars and consist of a central/oral disc and five radial arms. Serpent stars differ from other brittle stars because they have smooth arms, instead of spiny ones. The body consists of thick dermal tissue that is supported by small bone-like structures, called ossicles. The mouth is located on the underside of the oral disc and metabolic waste excretion occurs through simple diffusion across permeable regions of the body wall. There is no sexual dimorphism (external differences between males and females) in this genus and reproduction occurs through broadcasting eggs and sperm into the water column. Reproduction in Ophioderma spp. has not been reported in the home aquarium and there is limited information about their larval development. Ophioderma spp. feed on detritus and other decaying organic matter. One interesting characteristic is that serpent stars, like sea stars, can re-grow their arms if attacked. Some brittle stars even detach their arm(s) when threatened as a sort of token meal for the predator before briskly moving for shelter.

Natural Habitat

Serpent stars are found throughout the world and Ophioderma spp. are typically encountered in tropical and subtropical seas. They live under rocks, in seagrass beds, crevices and other dark recesses. Some even live in or on corals, gorgonians, and sponges. Serpent stars are nocturnal and generally stay hidden throughout the day. They occur in shallow, inter-tidal zones and offshore environments. The color of Ophioderma spp. varies greatly from brown to beautiful red and some also have attractive banded arms. Their biological importance is significant due to their diet of decaying organic matter and detritus. Most aquarium specimens are collected in shallow habitats by flipping over loose rubble and small rocks.

Aquarium Care

Serpent stars are easy to care for and are a key component of any modern reef aquaria. When selecting one for purchase, make sure that there are no signs of infection. Sometimes rough shipping (temperature, low pH and oxygen) can cause arms to detach and subsequent infection occurs on both the remaining arm(s) and oral disk. Early signs of infection may include a whitish-grey area that eventually creates an open sore and concave oral disk. Serpent stars can be kept in small aquariums (less than 10 gallons) and require some rocks or other hiding places to thrive. It is possible to keep serpent stars in a small tank with as little as some sand, a rock and an airstone. Due to their permeable skin, care should be taken when handling and salinity should be closely monitored. These animals are always interesting to watch, especially when feeding. While they primarily "clean" the bottom by eating detritus, they also scavenge for any uneaten fish food, fish feces and other waste. Diet in the aquarium consists of many different frozen and pelleted foods, but they particularly like mysis shrimp and other small crustaceans. In a naturally balanced reef tank, it is ideal to have one per 10-15 gallons. If there is a heavy fish load and lots of live rock, this number can be increased.