Damselfish can see colour

You ever wondered if the myriad of colourful reef fish are actually able to see colour themselves. It seems they have to, right? However until now there has been no conclusive scientific evidence that they can.

Lat week the Journal of Experimental Biology published an article that proves by behavioural experiments conducted at Australia's Lizard Island Research Station that damselfish can see colour.

From the inside JEB repoprt:

'According to Siebeck, capturing the yellow fish was relatively straightforward. Equipped with a hand net and Ziploc bag, she and Litherland went SCUBA diving, trapping fish on the island's reefs ready to test their colour recognition skills. But learning how to train the fish was far more tricky; the team had to get into `fish psychology' to learn how to tell the fish what to do. Fortunately the fish turned out to be quick learners, `possibly because they are territorial and quickly recognise novel objects placed in their territory' explains Siebeck. According to Siebeck the damselfish try to nudge intruders out of their territory. So she and Wallis took advantage of this behaviour and trained each fish to nudge 10 times at a coloured latex finger before rewarding them with a fish food snack. Having trained one group of fish to recognise a rubber finger painted yellow and another group to recognise a finger painted blue, Siebeck and Wallis offered each fish a choice between blue and yellow fingers and watched to see which colour the fish opted for. Amazingly the yellow trained fish selected the yellow finger on 95% of occasions, and the blue trained fish got the blue finger more than 91% of the time.'

More at:

http://jeb.biologists.org/cgi/content/full/211/3/ii

Contributed by Tim Hochgrebe added 2008-01-26