can colour be called energy?

Colour, in the sense of "visible light wavelength", can be called a degree of energy, or rather a degree of power.

Energy of a photon increases when the wavelength decreases. Accordingly the color of the photon changes from red to green to blue.

The colour that our eyes see may come from a mixture of different wavelengths, so care should be taken to avoid confusion when translating colours to energies.

Yes, of course. Colour is an electromagnetic wave, and an electromagnetic wave transports energy.

The word "colour" is also used to mean "selective reflectance". If I put a red brick into a dark room, it looks black in the darkness, but if I shine a white light on it, it selects the red waves in the light and reflects them back to me. A white object would be the same colour as the light shining on it.