 The colour of the light does not matter, but it has been shown that they react more strongly to underwater lights between the intensities of 1.5 to 2.5 lx, with peak ranges of 2.5 to 10.0 lx.Bigfin reef squids and the common octopus ("Octopus vulgaris") were studied to resolve a century-long debate over whether cephalopods can hear.Unlike fishes, cephalopods do not possess air-filled swim bladders, which might amplify sound waves travelling in water.