Sea pens are colonial marine cnidarians belonging to the order Pennatulacea. There are 16 families within the order; they are thought to have a cosmopolitan distribution in tropical and temperate waters worldwide.
A zebrafish is a tropical freshwater fish in the minnow family. These to odd looking creatures are 2 day old zebra fish larvae. Picture Credit: Jurgen Berger and Mahendra Sonawane, both employees at the Max Planck Institute for Developmental Biology.