AROUND & ABOUT WILLS EYE: JUST ANOTHER DAY AT THE OFFISH (3/2/15)

It was another day at the offish for a couple of domesticated Glaucoma Gold Fish enjoying a casual swim in their state-of-the-art tank located on the 11th-floor waiting room.

"[Gold Fish] are one of the most studied animals in the field of visual perception and cognition. They can perceive the same colours we do, which not even all primates can do, making them an ideal study animal. Juvenile goldfish are even bad at seeing the colour blue, but improve as they age, a pattern repeated in human infants. In one respect they are unlike us: whereas humans have three types of colour-sensing cells in our eyes, goldfish also have a fourth type of colour receptor that allows them to perceive ultraviolet light.  But despite this, their other three colour sensors are an excellent analogue for our own."
VIEW SOURCE: BBC EARTH STORY 
photos: roger barone/WILLS EYE HOSPITAL