Please DO NOT get a Fromia star for this size tank. Their small size is tragic because people assume they are suitable for small tanks. They are not.
Most Fromia stars will not survive in this tank.
They are among the most delicate and sensitive stars in this hobby, and most die within a month of acclimation shock. In fact most I have seen are dying at the LFS. These are NOT easy stars to keep...and there has been no success unless you've kept them 18 months (at least a year). There is a huge secondary spike in mortality at this time, due to starvation. Most people think they are eaten, but they are not...they starve.
It is very rare for them to take to spot feeding. Very rare, and I would not be positive it is spot feeding...but I certainly would not assume another individual will spot feed.
Please, Coral Keeper, these are very advanced animals to keep and they are not suitable for very small tanks. They require large STABLE systems. Such a star will almost CERTAINLY die in your size tank - most likely of acclimation issues or failure to maintain ideal water quality. Water quality must be consistent and PRISTINE.
They require very long acclimation times.
There are few stars suitable for this size tank due to the difficulty keeping parameters stable and lack of food for reef safe seastars.
I can only strongly discourage you from keeping these stars.
Success is measured in years, not months.
The micro stars, such as Asterina, which are very hardy, are suitable choices.