Red appears more than blue in the nebulae I have seen.

I am not getting very far on red as I dont know what I'm looking for, but the ocean corral reef looks blue, green, yellow.  Curios to see for yourself.  My hunch that red is a kind of blue or maybe the other way around.  Blue always felt much more than it looks, that it is not much like purple, as that color wheel fails to explain.