Why are reef animals and corals so colourful?

[Bjohn]

I found this interesting national article, it is old but I liked it. http://ngm.nationalgeographic.com/2005/05/coral-reefs/kaufman-text/1
Does anyone else have any articles they have found about why our reefs are so brilliantly coloured? Especially about the corals.

 

[808jaymakoa]

Good read.