The problem with the color of your image is that, from less than a certain illumination level, the color turns towards the blue. Compare with my image:
See that the streams coming from the companion in my image are yellowish but the stream at the end of the spiral arm of the main galaxy is clearly bluish. In your image all these streams, as well as the outer areas of the companion galaxy, are blue.
Did you make a different histogram / curves adjustment for each color channel? Which was the resulting color from Excalibrator? Remember that the ColorCalibration and BackgroundNeutralization tools must be applied always to linear images, never after delinearization of the data.