Hold on please!
First, these animals do not generally die quickly. They can take a month to die from acclimation shock and the tend to starve to death in about 9-12 months. They ONLY FEED ON LR and not on "algae" in the sense we think of...don't hope you get the exception that will take to spot feeding. I am not as worried in the 140...assuming it is a mature reef tank (6 months old with lots of LR), with pristine water parameters (1.025-1.026 specific gravity as well). That is a nice tank again assuming there is lots of LR.
PLEASE do not encourage anyone to put one in their tank because it hasn't died in 2 weeks! Assuming that it is in a 20g nano, it will almost certainly die of starvation, unless it is one of the few that does respond to direct spot feeding. This should not be an impulse purchase. Any Linckia related star (including Fromia) requires some serious research in care and acclimation!
The larger picture is generally called an "orange Linckia" (though it is quite probably not a Linckia but a relative)...the "red reef star" is typically a similar shape, but has hint of a black tip to the arm. This is a Fromia star, and if there is one that is a more finicky eater than a Linckia, that might well win the contest.
