Sand goby 23rd January 2015 Robin Somes Leave a comment Sand goby, Pomatoschistus minutus. The black/blue spot on the first dorsal fin is at the upper edge of the fin. The common goby has a similar spot, but it is positioned lower on the fin membrane, close to the body. Share this:EmailPrintLinkedInFacebookMorePocketRedditTumblrTwitterPinterest