Echinoderms, or sea stars, in general, are such amazing creatures. They have no brain and no blood. They propel themselves slowly via water pulpusion through a series of tubes in their arms. They have thousands of "suction cup" feet that can stick to anything. If they lose an arm, they grow it back. And the severed arm grows into a new starfish as well! They reproduce asexually. In addition, they are detritovres, scavenging and sifting through sand and rubble, eating bacterial film and other unknown wastes. Sea stars are incredibly strong and can even pry apart mollusk shells. They can also voluntarily prolapse their stomachs into the shell of a clam (or other mollusk), where it secretes digestive enzymes to puree the food. Dude! Without a doubt, these creatures are pretty amazing.
I knew they were sensitive creatures in the home aquarium but after having success with the shrimp, I decided to try one out. I asked the LFS about a small, reef-safe, peaceful starfish that would be easy to care for. He suggested the Linckia. They come in lots of colors (red, blue, purple, spotted). He got the reef-safe, peaceful part right (some starfish (the "bumpy" or "knobby" ones, in general) are extremely predatory and can become quite large, preying on your shrimp, crabs, snails, and fish!) but not the "easy to care for" part. Unfortunately, I found out later that most Linckias in home aquariums die within a few months either due to starvation or parasitic infections. Ugh! I HAVE to be more careful.
Orange Linckias grow to a max of 3-4" and are from the Indian Ocean. Despite their small size, keeping them is most successful in a large, well-established reef tank of 100-gallons or more with lots of live rock (at least 6 months old). Oops. This is probably because we don't know what they eat, and a larger, well-established tank is likely to provide them with a stable source of food. The linckias, like other sea stars are very sensitive creatures. They prefer a high salinity of 1.025 and will not tolerate fluctuations in temperature, salinity, pH, or other parameters. They require pristine water conditions (no nitrates). Like other invertebrates, copper medications (used for sick fish in a fish-only system or hospital tank) will kill them. In addition, they require a slow acclimation process, using the drip system of 3.5 hours. When selecting one, choose a healthy speciman that can right itself when flipped on its back. Also, avoid specimans with white, fluffy growths (often parasites) or other injuries.
I really hope Clementine makes it. She is verrry healthy. I actually only did a 1-hour acclimation (unknowingly). Our salinity is 1.023 so I'm slowly rising it to 1.025 over the next week or so. When I first put her in the tank, she landed on her back in the sand and immediately flipped herself over and climbed up the wall. She likes to be out front and center, on display. She's pretty active, moving all over the glass and rocks. I absolutely adore her. She's gorgeous.