Rock Prickleback      Xiphister mucosus



This fish is not an eel, but it certainly has an eel-like appearance.   It is a citizen of rocky habitats that are exposed to moderate wave action, where it can be found under rocks and algae at low tide. It is characterized by the greenish black body color with faint white markings around the base of the tail and white strips below the eyes (not seen in this top view).  The long dorsal fin starts right behind the head, unlike its cousin the Black Prickleback where the dorsal fin arises further back on the body.  This 9 inch specimen is half the size of a full grown individual which can reach up to 23 inches.


The pricklebacks are a family of fish that are characterized by long slender compressed bodies.  The dorsal fin goes the length of the body merging with the caudal fin.  The anal fin is also very long. The pectoral fins, near the gill covers, are very small to absent.  They are called pricklebacks because the dorsal fin is mostly composed of hard spiny rays with sharp tips (rays are supports of the fleshy fin).  There are around 20 species in the Pacific Northwest, many of which live in the subtidal zone and are only seen by divers .


A similar appearing group of fishes, called Gunnels, are shorter in total length, have a shorter anal fin and more often the anal and dorsal fins join the caudal fin.


The rock prickleback ranges from SE Alaska to southern California.  It is unique in that it seems to eat a high percentage of algae along with feeding on small animals.  It lays it's eggs under rocks and vegetation where the male coils around them for protection.