I have seen frogfishes before and have usually been able to pick them out from the patch of corals they paste themselves on. In their attempt to blend in, somehow something about their disguise usually gave them away, and it was usually because they carried a slightly different colour from their background.
It wasn't until I took the black and white shot above though, that I truly appreciated the effectiveness of their disguise.
Unlike divers, most fish are colourblind (only able to make out shadings of colour, shape and movement), which makes the disguise of this particular frogfish deadly effective.
