It's starving, and yes, it's unfortunately quite normal - not good, but normal.
Most filter feeding worms die of starvation in captivity - they are very particular about the size of what they eat. But sadly there are very few studies on the subject linking particular species to particular particle sizes... Or even effective ways to determine the species of your specimen.
They are, for the moment, best not attempted in captivity except in large, mature tanks that are heavily fed various micro foods. And then it's dicey.
The tiny fan worm colonies that grow on rock spontaneously - either white or red - are a good way to enjoy these kinds of beautiful worms. Either they are less picky, or the average tank provides the right food.
You could attempt to save this one by feeding a mix of phytoplankton and/or tiny foods like oyster eggs.