Keeping any animal in captivity is potentially a cruel thing to do. I’m therefore very keen to maximise the health of domesticated creatures.
Many fish have very advanced colour vision, so today’s invention is aimed at preserving what might be thought of as their mental health, by giving them some control over their environment.
It involves fitting their tank with a number of coloured lights. Each is wired to illuminate locally as a fish approaches. Fish will tend to congregate at positions which are lit in their preferred shade(s).
Each light in the tank could be placed opposite a simple photocell. The signal from each of these would depend on the number of fish occluding the lamp.
This could be used automatically to infer the distribution of fish and then to control which colours should be ‘on’ most frequently. This would enable the tank’s occupants to customise their own visual environment.
(It would interesting eg to see what spatial distributions developed within different subspecies and whether colour preference varied with the time of day).