text: do fish see in black and white or colour?   color.  (or if they're british fish, 'colour'.)  there are some famous experiments on color constancy in goldfish done by a professor named david ingle.  here's a picture of the cover of science magazine showing ingle's goldfish in front of some color swatches (scroll down). http://www.rowland.harvard.edu/organization/past_research/fishlab/fishlab.html