"Morphology and spectral sensitivities of retinal and extraretinal
photoreceptors in freshwater teleosts" by C. Kusmic and P. Gualtieri in Micron volume 31, p. 183-200, 2000, has a chart that shows where in the light spectrum the different absorbancy maximas are. THe chart lists like 30 species, but are broken into 4 groups:
Group 1 are strictly diurnal species that live just below the water surface or live in shallow water. Some of the species listed are the guppies and swordtails. They have maximas in the violet part of the spectrum, right at 410-415 nm, and some in the blue part 460 nm. So, these fish should be very good at picking up blue light.
Group 2 are midwater swimmers, like barbs. Most of them don't have the violet peak, but the blue peak is present in almost every species this paper looked at.
Group 3 are nocturnal species, mostly predators. Group 4 are also nocturnal bottom dweelers, like cory catfish or red tailed black sharks. These do not have the violet or blue maximas at all, only the red ones.
However, it is obvious that like a lot of life, no one blanket statement can be said about all fish, depending upon their habitat and activities, the way they detect light varies.
