There seems to be a wide-spread tradition in the blogosphere involving cute animal pictures (typically kittens) on Fridays. Dr. Myers, at Pharyngula, posts awesome pictures of cephalopods on Fridays. I think I'll try posting pictures of fish, since I can occasionally get away with telling people I'm an Ichthyologist.
This is a picture of a male guppy, from the population "CC". This guy is a descendant of fish collected in 2000 by Dr. Felix Breden and Heather Alexander, in the town of Cumana, Venezuela. Some people in the aquarium hobby trade refer to these fish as "Endler's Livebearers", after Dr. John Endler, a professor at the University of California, Santa Barbara. They breed readily with other guppies, so we don't consider them a separate species.