Subject: We humans use “colours as an important way to communicate hazards”. Fish use colours to avoid predation, to blend in with the environment and to communicate their readiness to be cleaned. These Bluestreak Fusiliers are wearing red because they are close to the reef, maybe looking to be cleaned or ready for a rest in the rubble of the reef. When out in the open water they dress in blue.
Technique: This image has been cropped, a lot. It is part of a wide-angle image. The entire picture itself is not interesting at all, but this fragment caught my attention. To make the best of this image I cut off more than 50%. I also erased some other fish and boosted the contrast and colours a bit.