It is hard to tell much from the small picture... but since you mentioned that this was a "frag"... so I am assuming that it is new to you and your system? SPS's often take weeks and months to settle down as to which color they will be in our tanks. And, moving from one tank to another, the lighting conditions change, flow changes... everything... which once again they will end up going thru changes. The exact same coral may be a deep blue in my tank... yet in your tank much lighter. Even having two of the same corals in the same tank, yet in different places, can cause a varience in color.
Just keep an eye on your frag, watching for any signs of problems. The color may continue changing to match your particular tank situation... don't be alarmed with that.