Not perhaps as cool as the eye of the tiger, but nevertheless, a pretty intricate system of rods, cones and chromophores. Not only that, but the recent work suggests that selective processing or different pathways for chromophore uptake in different photoreceptor types may be occurring. If so, this may have have ecological and functional implications, and this opens the door for future evolutionary studies. Read soon more from the article to be appear in Journal of Experimental Biology.
Saarinen PK, Pahlberg J, Herczeg G, Viljanen M, Karjalainen M, Shikano T, Merilä J & K Donner (2012) Spectral tuning by selective chromophore uptake in rods and cones of eight populations of nine-spined stickleback (Pungitius pungitius). Journal of Experimental Biology, in press.