Pete is the pro on seahorse behavior, but from experience I can tell you that my mustang female is, as well as the sunburst males, bad to get slow eating. I usually find that if I dont break down and target feed that the next meal becomes a little more enticing. They do have a tendency to slow down on meals, and even hide more often when mating. I have also noticed some being a little persnickity over their preference in food as well. I dont think you need to be too concerned unless she really stops eating. Does she look and act okay apart from this?