Fish might be able to see red
An article over at Nature.com.
Apparently, it is a common assumption that deep-sea fish cannot see red. Yet they just discovered a jellyfish that uses copepod shaped glowing red tentacles to catch supper. This would be strange, since scientists think only three fish are sensitive to red light, and all the others are not. However:
Haddock points out that deep-sea fish caught by researchers are now often sorted on deck under red light, in an attempt to preserve their visual apparatuses for study. Ironically, Haddock says, this would destroy any red-sensitive visual pigments.If this is so... Heh.
Follow the link above for the article, and a video.